Revised list of TBCs

author: kinitrupti 2017-05-12 18:40:35 +0530
committer: kinitrupti 2017-05-12 18:40:35 +0530
commit: d36fc3b8f88cc3108ffff6151e376b619b9abb01 (patch)
tree: 9806b0d68a708d2cfc4efc8ae3751423c56b7721 /Optical_Fiber_Communication
parent: 1b1bb67e9ea912be5c8591523c8b328766e3680f (diff)
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diff --git a/Optical_Fiber_Communication/Chapter10.ipynb b/Optical_Fiber_Communication/Chapter10.ipynb
deleted file mode 100755
index 22b4a658..00000000
--- a/Optical_Fiber_Communication/Chapter10.ipynb
+++ /dev/null
@@ -1,487 +0,0 @@
-{
- "metadata": {
-  "name": "",
-  "signature": "sha256:cf07634df992def504a143e6666719b95350cb053657de1ded2573417a8b0796"
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 10 : Optical Fiber System-II"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1: PgNo-505"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable initialisation\n",
-      "r=30.8*math.pow(10,-12) # electro optice coefficient in m/V\n",
-      "L=3*math.pow(10,-2) # length in m\n",
-      "y=1.3*math.pow(10,-6) # wavelength in m\n",
-      "n=2.1\n",
-      "d=30*math.pow(10,-6) # distance between the electrodes in m\n",
-      "V=(y*d)/(math.pow(n,3)*r*L) # voltage required to have a pi radian phase change in volt\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.3f %s' %(\" The voltage required to have a pi radian phase change  = \",V,\"volt\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The voltage required to have a pi radian phase change  =  4.558 volt\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2: PgNo-511"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "#Variable initialisation\n",
-      "a_fc=4 #fider cable loss in dB/km\n",
-      "aj=0.7 #splice loss in db/km\n",
-      "L=5 # length in km\n",
-      "a_cr1=4 # connector losses\n",
-      "a_cr2=3.5 # connector losses\n",
-      "CL=(a_fc+aj)*L+(a_cr1+a_cr2) # total channel loss in dB\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.f %s' %(\" The total channel loss = \",CL,\"dB\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The total channel loss =  31 dB\n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3: PgNo-517"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# variable initialisation\n",
-      "p=0.5*math.pow(10,-9) # pulse broadening in s/km\n",
-      "L=12 # length in km\n",
-      "\n",
-      "# calculations\n",
-      "Pt=p*math.sqrt(L) # with mode coupling, the total rms broadening in s\n",
-      "BT=20*math.pow(10,6)\n",
-      "DL=2*pow((2*Pt*BT*math.sqrt(2)),4) # dispersion equalization penalty in dB\n",
-      "Pt1=p*L # without mode coupling, the total rms broadening in s\n",
-      "DL1=2*math.pow((2*Pt1*BT*math.sqrt(2)),4) # without mode coupling, equalization penalty in dB\n",
-      "DL2=2*math.pow((2*Pt1*150*math.pow(10,6)*math.sqrt(2)),4) # without mode coupling,dispersion equalization penalty with 125 Mb/s\n",
-      "DL3=2*math.pow((2*Pt*125*math.pow(10,6)*math.sqrt(2)),4) # with mode coupling,dispersion equalization penalty with 125 Mb/s\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" With mode coupling, the total rms broadening = \",Pt*pow(10,9),\"ns\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The dispersion equalization penalty = \",DL*pow(10,4),\"dB\"))\n",
-      "print ('%s %.f %s' %(\"\\n without mode coupling, the total rms broadening = \",Pt1*pow(10,9),\"dB\"))\n",
-      "print ('%s %.3f %s' %(\"\\n without mode coupling, equalization penalty = \",DL1,\"dB\"))\n",
-      "print ('%s %.2f %s' %(\"\\n without mode coupling,dispersion equalization penalty with 125 Mb/s = \",DL2,\"dB\"))\n",
-      "print ('%s %.2f %s' %(\"\\n with mode coupling,dispersion equalization penalty with 125 Mb/s = \",DL3,\"dB\"))\n",
-      "print (\"\\n The answer is wrong in the textbook\")"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " With mode coupling, the total rms broadening =  1.73 ns\n",
-        "\n",
-        " The dispersion equalization penalty =  1.84 dB\n",
-        "\n",
-        " without mode coupling, the total rms broadening =  6 dB\n",
-        "\n",
-        " without mode coupling, equalization penalty =  0.027 dB\n",
-        "\n",
-        " without mode coupling,dispersion equalization penalty with 125 Mb/s =  83.98 dB\n",
-        "\n",
-        " with mode coupling,dispersion equalization penalty with 125 Mb/s =  0.28 dB\n",
-        "\n",
-        " The answer is wrong in the textbook\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Example 4: PgNo-522"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable initialisation\n",
-      "Pi=-2.5 # mean optical power launched into the fiber in dBm\n",
-      "Po=-45 # mean output optical power available at the receiver in dBm\n",
-      "a_fc=0.35 # fider cable loss in dB/km\n",
-      "aj=0.1 # splice loss in db/km\n",
-      "a_cr=1 # connector losses\n",
-      "Ma=6   # safety margin in dB\n",
-      "L=(Pi-Po-a_cr-Ma)/(a_fc+aj) # length in km when system operating at 25 Mbps\n",
-      "Po1=-35 #  mean output optical power available at the receiver in dBm\n",
-      "L1=(Pi-Po1-a_cr-Ma)/(a_fc+aj) # length in km when system operating at 350 Mbps\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The length when system operating at 25 Mbps = \",L,\"km\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The length when system operating at 350 Mbps = \",L1,\"km\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The length when system operating at 25 Mbps =  78.89 km\n",
-        "\n",
-        " The length when system operating at 350 Mbps =  56.67 km\n"
-       ]
-      }
-     ],
-     "prompt_number": 4
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5: PgNo-526"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# variable initialisation\n",
-      "Tx=-80 # transmitter output in dBm\n",
-      "Rx=-40 # receiver sensitivity in dBm\n",
-      "sm=32  # system margin in dB\n",
-      "L=10   # in km\n",
-      "fl=2*L # fider loss in dB\n",
-      "cl=1   # detector coupling loss in dB\n",
-      "tl=0.4*8 # total splicing loss in dB\n",
-      "ae=5  # angle effects & future splice in dB\n",
-      "ta=29.2 # total attenuation in dB\n",
-      "Ep=2.8 # excess power margin in dB\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.1f %s' %(\" The fider loss = \",fl,\"dB\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The total splicing loss = \",tl,\"dB\"))\n",
-      "print ('%s %.1f %s' %(\"\\n The fangle effects & future splice = \",ae,\"dB\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The total attenuation = \",ta,\"dB\"))\n",
-      "print ('%s %.1f %s' %(\"\\n The excess power margin = \",Ep,\"dB\"))\n",
-      "print (\"\\n Hence the system can operate with small excess power margin \")"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The fider loss =  20.0 dB\n",
-        "\n",
-        " The total splicing loss =  3.20 dB\n",
-        "\n",
-        " The fangle effects & future splice =  5.0 dB\n",
-        "\n",
-        " The total attenuation =  29.20 dB\n",
-        "\n",
-        " The excess power margin =  2.8 dB\n",
-        "\n",
-        " Hence the system can operate with small excess power margin \n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 6: PgNo-529"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# variable initialisation\n",
-      "Lc=1 # connector loss in db\n",
-      "Ls=5 # star coupler insertion loss in dB\n",
-      "af=2 # fider loss in dB\n",
-      "Ps=-14 # transmitted power in dBm\n",
-      "Pr=-49 # receiver sensitivity in dBm\n",
-      "sm=6 # system margin in dB\n",
-      "N=16.0\n",
-      "L=(Ps-Pr-Ls-4*Lc-(10*math.log(N))/math.log(10)-sm)/(2*af) # max transmission length in km when transmission star coupler is used\n",
-      "N1=32\n",
-      "L1=(Ps-Pr-Ls-4*Lc-(10*math.log(N1))/math.log(10)-sm)/(2*af) # max transmission length in km when reflection star coupler is used\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The max transmission length when transmission star coupler is used = \",L,\"km\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The max transmission length when reflection star coupler is used = \",L1,\"km\"))\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The max transmission length when transmission star coupler is used =  1.99 km\n",
-        "\n",
-        " The max transmission length when reflection star coupler is used =  1.24 km\n"
-       ]
-      }
-     ],
-     "prompt_number": 6
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 7: PgNo-531"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# variable declaration\n",
-      "y=860*math.pow(10,-9) # wavelength in m\n",
-      "L=5000 # length in m\n",
-      "X=0.024\n",
-      "dy=20*math.pow(10,-9) # spectral width in m\n",
-      "dts=6*math.pow(10,-9) # silica optical link rise time in s\n",
-      "dtr=8*math.pow(10,-9) # detector rise in s\n",
-      "c=3*math.pow(10,8)# speed of light in m/s\n",
-      "dtm=-(L*dy*X)/(c*y) # material dispersion delay time in s\n",
-      "id=2.5*math.pow(10,-12) # intermodel dispersion in s/m\n",
-      "dti=id*L # intermodel dispersion delay time\n",
-      "dtsy=math.sqrt(math.pow(dts,2)+math.pow(dtr,2)+math.pow(dtm,2)+math.pow(dti,2)) # system rise time in s\n",
-      "Br_max=0.7/dtsy # max bit rate for NRZ coding in bit/s\n",
-      "Br_max1=0.35/dtsy # max bit rate for RZ coding in bit/s\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The system rise time = \",dtsy*pow(10,9),\"ns\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The max bit rate for NRZ coding = \",Br_max/pow(10,6),\"Mbit/s\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The max bit rate for RZ coding = \",Br_max1/pow(10,6),\"Mbit/s\"))\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The system rise time =  18.51 ns\n",
-        "\n",
-        " The max bit rate for NRZ coding =  37.81 Mbit/s\n",
-        "\n",
-        " The max bit rate for RZ coding =  18.90 Mbit/s\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 8: PgNo-533"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "#variable declaration\n",
-      "Br=50*math.pow(10,6) # data rate in b/s\n",
-      "c=3*math.pow(10,8) # speed of light in m/s\n",
-      "n1=1.47\n",
-      "dl=0.02\n",
-      "n12=n1*dl # the difference b/w n1 and n2\n",
-      "L_si=(0.35*c)/(n12*Br) # transmission distance for Si fiber\n",
-      "L_GI=(2.8*c*math.pow(n1,2))/(2*n1*n12*Br) # transmission distance for GRIN fiber\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.3f %s' %(\" The transmission distance for Si fiber = \",L_si,\"m\"))\n",
-      "print ('%s %.f %s' %(\"\\n The transmission distance for GRIN fiber = \",L_GI,\"m\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The transmission distance for Si fiber =  71.429 m\n",
-        "\n",
-        " The transmission distance for GRIN fiber =  420 m\n"
-       ]
-      }
-     ],
-     "prompt_number": 8
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 9: PgNo-537"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Initialisation of variables\n",
-      "Br=20*math.pow(10,6) # data rate in b/s\n",
-      "c=3*math.pow(10,8)# speed of light in m/s\n",
-      "y=86*math.pow(10,-9)# wavelength in m\n",
-      "dy=30*math.pow(10,-9) # spectral width in m\n",
-      "X=0.024\n",
-      "Tb=1/Br\n",
-      "Lmax=(0.35*Tb*c*y)/(dy*X)# material dispersion limited transmission distance for RZ coding in m\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.3f %s' %(\" The material dispersion limited transmission distance = \",Lmax,\"m\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The material dispersion limited transmission distance =  627.083 m\n"
-       ]
-      }
-     ],
-     "prompt_number": 9
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 10: PgNo-543"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# variable declaration\n",
-      "y=860*math.pow(10,-9) # wavelength in m\n",
-      "c=3*math.pow(10,8) # speed of light in m/s\n",
-      "n1=1.47 \n",
-      "dl=0.02 \n",
-      "n12=n1*dl # the difference b/w n1 and n2\n",
-      "La=1/1000.0 # loss a in dB/m\n",
-      "Pr=-65 # receiver power in dB\n",
-      "Pt=-5 #transmitted power in dB\n",
-      "dy=30*math.pow(10,-9) # line width in m\n",
-      "X=0.024\n",
-      "Lmax=(0.35*c*y)/(dy*X) # material dispersion limited distance for RZ coding in m\n",
-      "L_GI=(1.4*c*n1)/(n12)# model dispersion limited distance for RZ coding in m\n",
-      "L_At=(Pt-Pr)/(La) # attenuation limited distance for RZ coding in m\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The material dispersion limited distance = \",Lmax/pow(10,10),\"*10^10*1/Br m\"))\n",
-      "print ('%s %.1f %s' %(\"\\n The model dispersion limited distance = \",L_GI/pow(10,10),\"*10^10*1/Br m\"))\n",
-      "print ('%s %.f %s' %(\"\\n The attenuation limited distance = \",L_At/pow(10,3),\"-20log(Br) km\"))\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The material dispersion limited distance =  12.54 *10^10*1/Br m\n",
-        "\n",
-        " The model dispersion limited distance =  2.1 *10^10*1/Br m\n",
-        "\n",
-        " The attenuation limited distance =  60 -20log(Br) km\n"
-       ]
-      }
-     ],
-     "prompt_number": 10
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
-\ No newline at end of file
diff --git a/Optical_Fiber_Communication/Chapter2.ipynb b/Optical_Fiber_Communication/Chapter2.ipynb
deleted file mode 100755
index 32f1c5a2..00000000
--- a/Optical_Fiber_Communication/Chapter2.ipynb
+++ /dev/null
@@ -1,721 +0,0 @@
-{
- "metadata": {
-  "name": "",
-  "signature": "sha256:ab3713dc22f25eef68710ebd9039d7fba92418b0de95b0ba48c70d6376545f8e"
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 2- Optical Fiber"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1: PgNo- 18"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable declaration\n",
-      "n1=1.55 # core refractive index\n",
-      "n2=1.50 #cladding refractive index\n",
-      "\n",
-      "# Calculations\n",
-      "x=math.asin(n2/n1) #Critical angle in radians\n",
-      "x1=x*180/math.pi   #Critical angle in degree\n",
-      "n_a=math.sqrt(math.pow(n1,2)-math.pow(n2,2)) # Numerical aperture\n",
-      "x_a=math.asin(n_a)*180/math.pi\n",
-      "x_a1=math.ceil(x_a) # Acceptance angle in Degree\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" Critical angle in degree= \", x1,\"degree\"))\n",
-      "print ('%s %.2f ' %(\"\\n Numerical aperture= \",n_a))\n",
-      "print ('%s %.1f %s' %(\"\\n Acceptance angle in degree= \",x_a1,\"degree\"))\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " Critical angle in degree=  75.41 degree\n",
-        "\n",
-        " Numerical aperture=  0.39 \n",
-        "\n",
-        " Acceptance angle in degree=  23.0 degree\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2:PgNo-21"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "# Variable declaration\n",
-      "\n",
-      "c=3*math.pow(10,8) #speed of light in m/s\n",
-      "v=2*math.pow(10,8) # in m/s\n",
-      "# calculations\n",
-      "n1=c/v\n",
-      "x=75    # in degree\n",
-      "n2=n1*math.sin((x*math.pi/180))\n",
-      "n_2=1.44\n",
-      "n_a=math.sqrt(math.pow(n1,2)-math.pow(n_2,2)) # numerical aperture\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f' %(\" Numerical aperture = \",n_a))\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " Numerical aperture =  0.42\n"
-       ]
-      }
-     ],
-     "prompt_number": 4
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3:PgNo-25"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math \n",
-      "\n",
-      "# Variable declaration\n",
-      "n1=1.50 # core refractive index\n",
-      "n2=1.47 # cladding refractive index\n",
-      "\n",
-      "# Calculations\n",
-      "dl=(n1-n2)/n1\n",
-      "n_a=n1*(math.sqrt(2*dl))# numerical aperture\n",
-      "x_a=(math.asin(n_a))*180/math.pi #acceptance angle in degree\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f' %(\" Numerical aperture = \",n_a))\n",
-      "print ('%s %.2f %s' %(\"\\n Acceptance angle in degree = \",x_a,\"degree\"))\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " Numerical aperture =  0.30\n",
-        "\n",
-        " Acceptance angle in degree =  17.46 degree\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 4:PgNo-27"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable declaration\n",
-      "n1=1.50 # core refractive index\n",
-      "n2=1.45 # cladding refractive index\n",
-      "\n",
-      "# Calculations\n",
-      "dl=(n1-n2)/n1\n",
-      "n_a=n1*(math.sqrt(2*dl)) # numerical aperture\n",
-      "x_a=(math.asin(n_a))*180/math.pi # acceptance angle in degree\n",
-      "x_c=(math.asin(n2/n1))*180/math.pi # critical angle in degree\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f' %(\" Numerical aperture = \",n_a))\n",
-      "print ('%s %.2f %s' %(\"\\n acceptance angle in degree = \",x_a,\"degree\"))\n",
-      "print ('%s %.2f %s' %(\"\\n critical angle in degree = \",x_c,\"degree\"))\n",
-      "\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " Numerical aperture =  0.39\n",
-        "\n",
-        " acceptance angle in degree =  22.79 degree\n",
-        "\n",
-        " critical angle in degree =  75.16 degree\n"
-       ]
-      }
-     ],
-     "prompt_number": 6
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5:PgNo- 32"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable declaration\n",
-      "dl=0.012\n",
-      "n_a=0.22  # numerical aperture\n",
-      "\n",
-      "# Calculations\n",
-      "n1=n_a/(math.sqrt(2*dl)) # core refractive index\n",
-      "n2=n1-(dl*n1)# cladding refractive index\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f' %(\" core refractive index = \",n1))\n",
-      "print ('%s %.2f' %(\"\\n cladding refractive index = \",n2))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " core refractive index =  1.42\n",
-        "\n",
-        " cladding refractive index =  1.40\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 6:PgNo-34"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable declaration\n",
-      "dl=0.012\n",
-      "n_a=0.22 # numerical aperture\n",
-      "\n",
-      "# Calculations\n",
-      "n1=n_a/(math.sqrt(2*dl)) # core refractive index\n",
-      "n2=n1-(dl*n1)# cladding refractive index\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f' %(\" core refractive index = \",n1))\n",
-      "print ('%s %.2f' %(\"\\n cladding refractive index = \",n2))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " core refractive index =  1.42\n",
-        "\n",
-        " cladding refractive index =  1.40\n"
-       ]
-      }
-     ],
-     "prompt_number": 8
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 7:PgNo-37"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable declaration\n",
-      "n2=1.59 # cladding refractive index\n",
-      "n_a=0.2 # numerical aperture\n",
-      "n_1=1.60 # core refractive index\n",
-      "n_o=1.33\n",
-      "\n",
-      "# Calculations\n",
-      "n1=math.sqrt(math.pow(n2,2)+math.pow(n_a,2)) # core refractive index\n",
-      "A=(math.sqrt(math.pow(n_1,2)-math.pow(n2,2)))/n_o\n",
-      "x_a=(math.asin(A))*180/math.pi        # acceptance angle in degree\n",
-      "x_c=(math.asin(n2/n1))*180/math.pi    #critical angle in degree\n",
-      "y=1300*math.pow(10,(-9))    # in meter\n",
-      "a=25*math.pow(10,(-6))      # in meter\n",
-      "v=(2*math.pi*a*n_a)/y\n",
-      "V=math.floor(v)\n",
-      "M=math.pow(V,2)/2 # number of modes transmitted\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" acceptance angle in degree = \",x_a,\"degree\"))\n",
-      "print ('%s %.2f %s' %(\"\\n critical angle in degree = \",x_c,\"degree\"))\n",
-      "print ('%s %d' %(\"\\n number of modes transmitted = \",M))\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " acceptance angle in degree =  7.72 degree\n",
-        "\n",
-        " critical angle in degree =  82.83 degree\n",
-        "\n",
-        " number of modes transmitted =  288\n"
-       ]
-      }
-     ],
-     "prompt_number": 9
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 8:PgNo-42"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable declaration\n",
-      "n1=1.50 # core refractive index\n",
-      "n2=1.47 # cladding refractive index\n",
-      "\n",
-      "# Calculations\n",
-      "dl=(n1-n2)/n1\n",
-      "n_a=n1*(math.sqrt(2*dl)) # numerical aperture\n",
-      "x_e=(math.asin(n_a))*180/math.pi # the maximum entrance angle in degree\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.1f' %(\" Numerical aperture = \",n_a))\n",
-      "print ('%s %.2f %s' %(\"\\n The maximum entrance angle in degree = \",x_e,\"degree\"))\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " Numerical aperture =  0.3\n",
-        "\n",
-        " The maximum entrance angle in degree =  17.46 degree\n"
-       ]
-      }
-     ],
-     "prompt_number": 10
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 9:PgNo-47"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable declaration\n",
-      "n1=1.44 # core refractive index\n",
-      "dl=0.02\n",
-      "\n",
-      "# Calculations\n",
-      "n_a=n1*math.sqrt(2*dl)\n",
-      "n_a=n1*(math.sqrt(2*dl)) # numerical aperture\n",
-      "x_a=(math.asin(n_a))*180/math.pi # acceptance angle in degree\n",
-      "\n",
-      "# Results\n",
-      "print \" Numerical aperture = \",n_a\n",
-      "print ('%s %.2f %s'%(\"\\n acceptance angle in degree = \",x_a,\"degree\"))\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " Numerical aperture =  0.288\n",
-        "\n",
-        " acceptance angle in degree =  16.74 degree\n"
-       ]
-      }
-     ],
-     "prompt_number": 11
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 10:PgNo-53"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable declaration\n",
-      "n1=1.50 # core refractive index\n",
-      "n2=(99.0/100.0)*1.50 # cladding refractive index\n",
-      "\n",
-      "# Calculations\n",
-      "x_c=math.asin(n2/n1)*(180/math.pi) # critical angle in degree\n",
-      "n_m=math.sqrt(math.pow(n1,2)-math.pow(n2,2)) # numerical aperture\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" critical angle = \",x_c,\"degree\"))\n",
-      "print ('%s %.2f' %(\"\\n numerical aperture = \",n_m))\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " critical angle =  81.89 degree\n",
-        "\n",
-        " numerical aperture =  0.21\n"
-       ]
-      }
-     ],
-     "prompt_number": 12
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11: PgNo-58"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable declaration\n",
-      "n1=1.50 # core refractive index\n",
-      "n2=1.45 # cladding refractive index\n",
-      "\n",
-      "# Calculations\n",
-      "n_m=math.sqrt(math.pow(n1,2)-math.pow(n2,2)) # numerical aperture\n",
-      "dl=(n1-n2)/n1 # fractional difference\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f' %(\" numerical aperture = \",n_m))\n",
-      "print ('%s %.2f' %(\"\\n fractional difference = \",dl))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " numerical aperture =  0.38\n",
-        "\n",
-        " fractional difference =  0.03\n"
-       ]
-      }
-     ],
-     "prompt_number": 13
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 12: PgNo-65"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable declaration\n",
-      "n1=1.46 # core refractive index\n",
-      "n2=1.45 # cladding refractive index\n",
-      "\n",
-      "# Calculations\n",
-      "x_c=(math.asin(n2/n1))*180/math.pi # critical angle in degree\n",
-      "n_m=math.sqrt(math.pow(n1,2)-math.pow(n2,2)) # numerical aperture\n",
-      "x_a=(math.asin(n_m))*180/math.pi # acceptance angle in degree\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" critical angle = \",x_c,\"degree\"))\n",
-      "print ('%s %.2f %s' %(\"\\n acceptance angle = \",x_a,\"degree\"))\n",
-      "print ('%s %.2f' %(\"\\n numerical aperture = \",n_m))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " critical angle =  83.29 degree\n",
-        "\n",
-        " acceptance angle =  9.82 degree\n",
-        "\n",
-        " numerical aperture =  0.17\n"
-       ]
-      }
-     ],
-     "prompt_number": 14
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 13: PgNo-67"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "# Variable declaration\n",
-      "n_m=0.204 #numerical aperture\n",
-      "dl=0.01 # index difference\n",
-      "\n",
-      "# Calculations\n",
-      "n1=n_m/(math.sqrt(2*dl)) # core refractive index\n",
-      "n2=n1*(1-dl) # cladding refractive index\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f' %(\" core refractive index = \",n1))\n",
-      "print ('%s %.2f' %(\"\\n cladding refractive index = \",n2))\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " core refractive index =  1.44\n",
-        "\n",
-        " cladding refractive index =  1.43\n"
-       ]
-      }
-     ],
-     "prompt_number": 15
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14: PgNo-71"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "# Variable declaration\n",
-      "\n",
-      "n1=1.46 #core refractive index\n",
-      "dl=0.01 # index difference\n",
-      "\n",
-      "# Calculations\n",
-      "n_2=n1-(n1*dl) # cladding refractive index\n",
-      "x_c=(math.asin(n_2/n1))*180/math.pi #critical angle in degree\n",
-      "n_m=math.sqrt(math.pow(n1,2)-math.pow(n_2,2)) # numerical aperture\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" critical angle = \",x_c,\"degree\"))\n",
-      "print ('%s %.2f' %(\"\\n numerical aperture = \",n_m))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " critical angle =  81.89 degree\n",
-        "\n",
-        " numerical aperture =  0.21\n"
-       ]
-      }
-     ],
-     "prompt_number": 16
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 15: PgNo-76"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "# Variable declaration\n",
-      "n1=1.50 # core refractive index\n",
-      "n2=1.45 # cladding refractive index\n",
-      "\n",
-      "# Calculations\n",
-      "x_c=(math.asin(n2/n1))*180/math.pi # critical angle in degree\n",
-      "n_m=math.sqrt(math.pow(n1,2)-math.pow(n2,2)) # numerical aperture\n",
-      "x_a=(math.asin(n_m))*180/math.pi # acceptance angle in degree\n",
-      "n_c=math.pow((n_m),2)*100 # percentage of light\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" critical angle= \",x_c,\"degree\"))\n",
-      "print ('%s %.2f %s' %(\"\\n acceptance angle= \",x_a,\"degree\"))\n",
-      "print ('%s %.2f' %(\"\\n numerical aperture= \",n_m))\n",
-      "print ('%s %.2f %s'%(\"\\n percentage of light= \",n_c,\"%\"))\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " critical angle=  75.16 degree\n",
-        "\n",
-        " acceptance angle=  22.59 degree\n",
-        "\n",
-        " numerical aperture=  0.38\n",
-        "\n",
-        " percentage of light=  14.75 %\n"
-       ]
-      }
-     ],
-     "prompt_number": 17
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 16: PgNo-81"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable declaration\n",
-      "n1=1.50 # core refractive index\n",
-      "dl=0.01 # index difference\n",
-      "\n",
-      "# Calculations\n",
-      "n_m=n1*(math.sqrt(2*dl)) # numerical aperture\n",
-      "x_a=math.pi*math.pow((n_m),2) # acceptance angle in radian\n",
-      "n2_1=(1-dl) # the ratio of n2 to n1\n",
-      "x_c=(math.asin(n2_1))*180/math.pi # critical angle in degree\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f'%(\" numerical aperture= \",n_m))\n",
-      "print ('%s %.2f %s' %(\"\\n acceptance angle= \",x_a,\"radian\"))\n",
-      "print ('%s %.2f %s'%(\"\\n critical angle= \",x_c,\"degree\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " numerical aperture=  0.21\n",
-        "\n",
-        " acceptance angle=  0.14 radian\n",
-        "\n",
-        " critical angle=  81.89 degree\n"
-       ]
-      }
-     ],
-     "prompt_number": 18
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
-\ No newline at end of file
diff --git a/Optical_Fiber_Communication/Chapter3.ipynb b/Optical_Fiber_Communication/Chapter3.ipynb
deleted file mode 100755
index 4ff5c94e..00000000
--- a/Optical_Fiber_Communication/Chapter3.ipynb
+++ /dev/null
@@ -1,1352 +0,0 @@
-{
- "metadata": {
-  "name": "",
-  "signature": "sha256:2b710cf5b5be9f51b281cf20f926c177245f0b5c79ffccf88ed3e06dd1ffcbfa"
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 3- Optical Fiber Fabrication"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example1: PgNo-83"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# variable declaration\n",
-      "n1=1.50 # core refractive index\n",
-      "n2=1.48 # cladding refractive index\n",
-      "y=1.3*math.pow(10,(-6))\n",
-      "m=1000 # the no. of models\n",
-      "\n",
-      "# Calculations\n",
-      "v=math.sqrt(2*m)\n",
-      "a=(v*y)/(2*math.pi*(math.sqrt(pow(n1,2)-math.pow(n2,2)))*math.pow(10,6)) # core radius in micrometer\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2e %s' %(\" core radius= \",a ,\"micrometer\"))\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " core radius=  3.79e-11 micrometer\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example2: PgNo-83"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable declaration\n",
-      "n1=1.505 # core refractive index\n",
-      "n2=1.502 # cladding refractive index\n",
-      "\n",
-      "# Calculations\n",
-      "n_m=math.sqrt(math.pow(n1,2)-math.pow(n2,2)) # numerical aperture\n",
-      "y=1.3*math.pow(10,(-6))\n",
-      "v=2.4\n",
-      "a=(v*y)/(2*math.pi*(math.sqrt(math.pow(n1,2)-math.pow(n2,2))))*math.pow(10,6)# core radius in micrometer\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f'%(\" numerical aperture= \",n_m))\n",
-      "print ('%s %.3f %s' %(\"\\n core radius= \",a,\"micrometer\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " numerical aperture=  0.09\n",
-        "\n",
-        " core radius=  5.228 micrometer\n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example3: PgNo-84"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "# Variable declaration\n",
-      "\n",
-      "n1=1.5 # core refractive index\n",
-      "dl=0.01 # index difference\n",
-      "m=0 # for the dominant mode\n",
-      "v=0 # for the dominant mode\n",
-      "y=1.3 # in micrometer\n",
-      "a=5.0 # radius in micrometer\n",
-      "\n",
-      "# Calculations\n",
-      "k=(2*math.pi)/y\n",
-      "b=math.pow(k,2)*math.pow(n1,2)-(2*k*n1*math.sqrt(2*dl))/a\n",
-      "B=math.sqrt(b) # propagation constant in rad/um\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.3f %s' %(\" propagation constant= \",B,\"rad/um\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " propagation constant=  7.221 rad/um\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example4: PgNo-86"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Printing the results\n",
-      "b=1/2 # propagtion constant\n",
-      "print (\" normalised propagtion constant\")\n",
-      "print (\"\\n B=(pow((b/k),2)-pow(n2,2))/(pow(n1,2)-pow(n2,2))\")\n",
-      "print (\"\\n thus when b=1/2\")\n",
-      "print (\"\\n B=k*sqrt(pow(n2,2)+b*(pow(n1,2)-pow(n2,2))\")\n",
-      "print (\"\\n B=k*sqrt(pow(n1,2)-pow(n2,2)/2)\")\n",
-      "print (\"\\n which gives its rms value\")"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " normalised propagtion constant\n",
-        "\n",
-        " B=(pow((b/k),2)-pow(n2,2))/(pow(n1,2)-pow(n2,2))\n",
-        "\n",
-        " thus when b=1/2\n",
-        "\n",
-        " B=k*sqrt(pow(n2,2)+b*(pow(n1,2)-pow(n2,2))\n",
-        "\n",
-        " B=k*sqrt(pow(n1,2)-pow(n2,2)/2)\n",
-        "\n",
-        " which gives its rms value\n"
-       ]
-      }
-     ],
-     "prompt_number": 4
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example5: PgNo-87"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable declaration\n",
-      "n1=3.6 #core refractive index\n",
-      "n2=3.3 # cladding refractive index\n",
-      "d=2.0 # thickness in um\n",
-      "y=0.8 # wavelength in um\n",
-      "\n",
-      "# Calculations\n",
-      "m=(2*d*math.sqrt(math.pow(n1,2)-math.pow(n2,2))/y) # total no. of models allowed\n",
-      "M=math.ceil(m) # total no. of models allowed\n",
-      "\n",
-      "print \" Total no. of models allowed= \",int(M)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " Total no. of models allowed=  8\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example6: PgNo-88"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Initialisation of variables\n",
-      "n1=1.48 # core refractive index\n",
-      "a=40*(math.pow(10,-6)) #core radius in meter\n",
-      "dl=0.015 # index difference\n",
-      "y=0.85*(math.pow(10,-6)) # wavelength in um\n",
-      "\n",
-      "# Calculations\n",
-      "v=(2*math.pi*a*n1*math.sqrt(2*dl))/y # normalised frequency\n",
-      "M=math.pow(v,2)/2\n",
-      "m=math.ceil(M) # the total no. of guided  modes\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f' %(\" normalised frequency= \",v))\n",
-      "print \"\\n The total no. of guided  modess = \",int(m)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " normalised frequency=  75.80\n",
-        "\n",
-        " The total no. of guided  modess =  2873\n"
-       ]
-      }
-     ],
-     "prompt_number": 6
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example7: PgNo-89"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Initialisation of variables\n",
-      "n1=1.46 # core refractive index\n",
-      "dl=0.015 # index difference\n",
-      "a=30*(math.pow(10,-6))# core radius in meter\n",
-      "y=0.85*(math.pow(10,-6)) #wavelength in um\n",
-      "\n",
-      "# calcualtions\n",
-      "n2=n1-(n1*dl)# cladding refractive index\n",
-      "v=(2*math.pi*a*n1*math.sqrt(2*dl))/y # normalised frequency\n",
-      "M=math.pow(v,2)/2 # the total no. of guided  modes\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f' %(\" Cladding refractive index= \",n2))\n",
-      "print ('%s %.3f'%(\"\\n Normalised frequency= \",v))\n",
-      "print \"\\n The total no. of guided  modes = \",int(M)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " Cladding refractive index=  1.44\n",
-        "\n",
-        " Normalised frequency=  56.078\n",
-        "\n",
-        " The total no. of guided  modes =  1572\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example8: PgNo-91"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Initialisation of variables\n",
-      "n1=1.5 # core refractive index\n",
-      "dl=0.01 # index difference\n",
-      "M=1100 # the total no. of guided  modes\n",
-      "y=1.3*(math.pow(10,-6)) # wavelength in um\n",
-      "v=math.sqrt(2*M)# normalised frequency\n",
-      "\n",
-      "# Calculations\n",
-      "a=(v*y)/(2*math.pi*n1*math.sqrt(2*dl))*math.pow(10,6) #core radius in meter\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f' %(\" Normalised frequency= \",v))\n",
-      "print ('%s %.2f %s' %(\"\\n The diameter of the fiber core = \",2*a,\"um\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " Normalised frequency=  46.90\n",
-        "\n",
-        " The diameter of the fiber core =  91.50 um\n"
-       ]
-      }
-     ],
-     "prompt_number": 8
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example9: PgNo-91"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Initialisation of variables\n",
-      "n1=1.45 # core refractive index\n",
-      "n_m=0.16 # numerical aperture\n",
-      "\n",
-      "# Calculations\n",
-      "a=30*math.pow(10,-6) # core radius in micrometer\n",
-      "y=0.5*(math.pow(10,-6)) # wavelength in um\n",
-      "v=(2*math.pi*a*n_m)/y #normalised frequency\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f' %(\" Normalised frequency= \",v))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " Normalised frequency=  60.32\n"
-       ]
-      }
-     ],
-     "prompt_number": 9
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example10: PgNo-93"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Initialisation of variables\n",
-      "n1=3.6 # core refractive index\n",
-      "n2=3.56 # cladding refractive index\n",
-      "y=0.85*(math.pow(10,-6))# wavelength in um\n",
-      "m=1\n",
-      "n=0\n",
-      "v_c=2.405 # for planner guide\n",
-      "\n",
-      "# Calculations\n",
-      "a=(v_c*y)/(2*math.pi*math.sqrt(math.pow(n1,2)-math.pow(n2,2)))# core radius in micrometer\n",
-      "\n",
-      "print ('%s %.2f %s' %(\"The max thickness= \",a*pow(10,6),\"um\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The max thickness=  0.61 um\n"
-       ]
-      }
-     ],
-     "prompt_number": 10
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example11: PgNo-94"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# variable declaration\n",
-      "n1=1.5 #core refractive index\n",
-      "y=1.3*(math.pow(10,-6)) # wavelength in um\n",
-      "M=1100 #  total no. of models\n",
-      "dl=0.01 # index difference\n",
-      "\n",
-      "# Calculations\n",
-      "v=math.sqrt(2*M)\n",
-      "V=math.ceil(v)\n",
-      "a=(V*y)/(2*math.pi*n1*math.sqrt(2*dl))*math.pow(10,6) # core radius in micrometer\n",
-      "a1=math.ceil(a)# core radius in micrometer\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\"The core diameter= \",2*a1,\"um\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The core diameter=  92.00 um\n"
-       ]
-      }
-     ],
-     "prompt_number": 11
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example12: PgNo-96"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Initialisation of variables\n",
-      "n1=1.45 # core refractive index\n",
-      "dl=0.015 # index difference\n",
-      "\n",
-      "# Calculations\n",
-      "y=0.85*(math.pow(10,-6)) # wavelength in meter\n",
-      "v=2.4*math.pow((1+(2/2)),(0.5))# Max normalised frequency\n",
-      "a=(v*y)/(2*math.pi*n1*math.pow((2*dl),(0.5))) # Max core radius in m\n",
-      "d=2*a # The max core diameter in meter\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.3f %s'%(\" The max core diameter in meter= \",d*pow(10,6),\"um\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The max core diameter in meter=  3.657 um\n"
-       ]
-      }
-     ],
-     "prompt_number": 12
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example13: PgNo-98"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable Initialisation\n",
-      "n1=1.48 #core refractive index\n",
-      "n2=1.46 # cladding refractive index\n",
-      "a=2.5   # radius in um\n",
-      "y=0.85  # wavelength in um\n",
-      "dl=(n1-n2)/n1 # index difference\n",
-      "v=(2*math.pi*a*n1*math.pow((2*dl),(0.5)))/y #the normaised frequency\n",
-      "M=(v*v)/2 # number of modes\n",
-      "print \" The number of modes= \",int(M)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The number of modes=  10\n"
-       ]
-      }
-     ],
-     "prompt_number": 13
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example14: PgNo-101"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Initialisation of variables\n",
-      "a=25 # radius in um\n",
-      "y=1.3 # wavelength in um\n",
-      "v=26.6 # the normaised frequency\n",
-      "NA=(v*y)/(2*math.pi*a) #Numerical aperture\n",
-      "a_c=math.pi*math.pow((NA),2)\n",
-      "M=(v*v)/2\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.3f' %(\" The number of modes= \", NA))\n",
-      "print ('%s %.3f' %(\"\\n The number of modes= \", a_c))\n",
-      "print (\"\\n Answer in textbook is wrong\")\n",
-      "print \"\\n The number of modes= \",int(M)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The number of modes=  0.220\n",
-        "\n",
-        " The number of modes=  0.152\n",
-        "\n",
-        " Answer in textbook is wrong\n",
-        "\n",
-        " The number of modes=  353\n"
-       ]
-      }
-     ],
-     "prompt_number": 14
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example15: PgNo-103"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Declaration of variables\n",
-      "n1=1.49 # core refractive index\n",
-      "n2=1.47 # cladding refractive index\n",
-      "a=2  # radius in um\n",
-      "dl=(n1-n2)/n1 # index difference\n",
-      "v_c=2.405\n",
-      "\n",
-      "# calculations\n",
-      "y_c=(2*math.pi*a*n1*math.pow((2*dl),(0.5)))/v_c # cut off wavelength in um\n",
-      "Y=1.31 # wavelength in um\n",
-      "A=(v_c*Y)/(2*math.pi*n1*math.pow((2*dl),(0.5))) # min core radius in um\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.3f %s' %(\" The cut off wavelength = \",y_c,\"um\"))\n",
-      "print ('%s %.3f %s' %(\"\\n The min core radius = \",A,\"um\"))\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The cut off wavelength =  1.276 um\n",
-        "\n",
-        " The min core radius =  2.054 um\n"
-       ]
-      }
-     ],
-     "prompt_number": 15
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example16: PgNo-105"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Initialisation of variables\n",
-      "a=25 # radius in um\n",
-      "NA=0.3 # Numerical aperture\n",
-      "y=1 # wavelength in um\n",
-      "v=(2*math.pi*a*NA)/y # the normalised frequency\n",
-      "V=47.1 # the normalised frequency\n",
-      "M=(V*V)/4 # The mode volume\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f' %(\" The normalised frequency = \",v))\n",
-      "print \"\\n The mode volume = \",int(M),\"guided modes\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The normalised frequency =  47.12\n",
-        "\n",
-        " The mode volume =  554 guided modes\n"
-       ]
-      }
-     ],
-     "prompt_number": 16
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example17: PgNo-107"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# variable declaration\n",
-      "n1=1.46 # core refractive index\n",
-      "a=4.5   # radius in um\n",
-      "dl=0.0025 # relative index difference\n",
-      "v_c=2.405\n",
-      "\n",
-      "# calculations\n",
-      "y_c=(2*math.pi*a*n1*math.pow((2*dl),(0.5)))/v_c # cut off wavelength in um\n",
-      "\n",
-      "print ('%s %.3f %s' %(\" The cut off wavelength = \",y_c,\"um\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The cut off wavelength =  1.214 um\n"
-       ]
-      }
-     ],
-     "prompt_number": 17
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example18: PgNo-109"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Initialisation of variables\n",
-      "n1=1.5 #core refractive index\n",
-      "n2=1.45 # cladding refractive index\n",
-      "a=50 # radius in um\n",
-      "y=1.3 #operating wavelength in um\n",
-      "\n",
-      "# calculations\n",
-      "NA=math.sqrt(math.pow(n1,2)-math.pow(n2,2)) # numerical aperture\n",
-      "N_A=0.38 \n",
-      "v=(2*math.pi*a*N_A)/y # cut of numbers\n",
-      "M=math.pow(v,2)/2 # number of modes\n",
-      "\n",
-      "print ('%s %.2f'%(\" The cut of numbers = \",v))\n",
-      "print \"\\n The number of modes = \",int(M)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The cut of numbers =  91.83\n",
-        "\n",
-        " The number of modes =  4216\n"
-       ]
-      }
-     ],
-     "prompt_number": 18
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example19: PgNo-111"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable initialisation\n",
-      "n1=1.53 # core refractive index\n",
-      "n2=1.5 # cladding refractive index\n",
-      "y=1.5 # operating wavelength in um\n",
-      "\n",
-      "# calculation\n",
-      "NA=math.sqrt(math.pow(n1,2)-math.pow(n2,2)) # numerical aperture\n",
-      "a=(2.405*y)/(2*math.pi*NA)# max radius in um\n",
-      "\n",
-      "print ('%s %.2f %s' %(\" The max core radius = \",a,\"um\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The max core radius =  1.90 um\n"
-       ]
-      }
-     ],
-     "prompt_number": 19
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example20: PgNo-112"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# variable declaration\n",
-      "a=25 # max radius in um\n",
-      "y=0.8 # operating wavelength in um\n",
-      "NA=0.343 # numerical aperture\n",
-      "v=(2*math.pi*a*NA)/y # v-number\n",
-      "M=math.pow(v,2)/2 #number of modes\n",
-      "\n",
-      "print ('%s %.6f' %(\" The v-number = \",v))\n",
-      "print \"\\n The number of modes = \",int(M)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The v-number =  67.347893\n",
-        "\n",
-        " The number of modes =  2267\n"
-       ]
-      }
-     ],
-     "prompt_number": 20
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example21: PgNo-114"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Initialisation of variables\n",
-      "n1=1.5 #core refractive index\n",
-      "NA=0.38 # numerical aperture\n",
-      "v=75 # v-number\n",
-      "y=1.3 # operating wavelength in um\n",
-      "a=(v*y)/(2*math.pi*NA) # core radius in um\n",
-      "n2=math.sqrt(math.pow(n1,2)-math.pow(NA,2))# cladding refractive index\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The core radius = \",a,\"um\"))\n",
-      "print ('%s %.2f' %(\"\\n The cladding refractive index = \", n2))\n",
-      "print (\"\\n answer in textbook is wrong \")"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The core radius =  40.84 um\n",
-        "\n",
-        " The cladding refractive index =  1.45\n",
-        "\n",
-        " answer in textbook is wrong \n"
-       ]
-      }
-     ],
-     "prompt_number": 21
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example22: PgNo-117"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "#Initialisation of variables\n",
-      "y=1.2 # operating wavelength in um\n",
-      "w=5 # spot size in um\n",
-      "x=(2*y)/(math.pi*w) # the divergence angle in degree\n",
-      "\n",
-      "# results\n",
-      "print ('%s %.3f %s' %(\" The divergence angle = \",x,\"degree\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The divergence angle =  0.153 degree\n"
-       ]
-      }
-     ],
-     "prompt_number": 22
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example23: PgNo-119"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Initialisation of variables\n",
-      "n1=1.46 # core refractive index\n",
-      "a=4.5 # core radius in um\n",
-      "dl=0.0025 # relative index difference\n",
-      "NA=n1*(math.sqrt(2*dl)) # numerical aperture\n",
-      "v=2.405\n",
-      "y=(2*math.pi*a*NA)/(v) # cut off wavelength in um\n",
-      "\n",
-      "print ('%s %.3f %s' %(\" The cut off wavelength = \",y,\"um\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The cut off wavelength =  1.214 um\n"
-       ]
-      }
-     ],
-     "prompt_number": 23
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example24: PgNo-121"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# variable declaration\n",
-      "n1=1.5 # core refractive index\n",
-      "n2=1.47 # cladding refractive index\n",
-      "y1=0.87 # operating wavelength in um\n",
-      "y2=1.5 # operating wavelength in um\n",
-      "a=25.0 # max radius in um\n",
-      "\n",
-      "# Calculations\n",
-      "NA=math.sqrt(math.pow(n1,2)-math.pow(n2,2)) # numerical aperture\n",
-      "v1=(2*math.pi*a*NA)/y1\n",
-      "v2=(2*math.pi*a*NA)/y2\n",
-      "al=2.0 # parabolic index profile for GRIN\n",
-      "M1=(al/(al+2))*(math.pow(v1,2)/2)# number of modes\n",
-      "M2=(al/(al+2))*(math.pow(v2,2)/2)# number of modes\n",
-      "\n",
-      "# Results\n",
-      "print \" The number of modes at 870 nm = \",int(M1),\"um\"\n",
-      "print \"\\n The number of modes = \",int(M2),\"um\"\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The number of modes at 870 nm =  726 um\n",
-        "\n",
-        " The number of modes =  244 um\n"
-       ]
-      }
-     ],
-     "prompt_number": 24
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example25: PgNo-122"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Initialisation of variables\n",
-      "n1=1.5 # core refractive index\n",
-      "n2=1.46 # cladding refractive index\n",
-      "v=2.4 # cut off parameter\n",
-      "y=0.85 # operating wavelength in um\n",
-      "\n",
-      "# Calculations\n",
-      "NA=math.sqrt(math.pow(n1,2)-math.pow(n2,2)) # numerical aperture\n",
-      "a=(v*y)/(2*math.pi*NA)# max radius in um\n",
-      "w=v*a # spot size\n",
-      "x=(2*y)/(3.4*w) # divergence angle in degree\n",
-      "d=50 # distance in meter\n",
-      "w_s=(y*d)/(math.pi*w) # spot size at 50 meter\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The numerical aperture = \",NA,\"um\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The max core radius = \",a,\"um\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The spot size = \",w,\"um\"))\n",
-      "print ('%s %.3f %s' %(\"\\n The divergence angle = \",x,\"degree\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The spot size at 50 meter = \",w_s,\"m\"))\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The numerical aperture =  0.34 um\n",
-        "\n",
-        " The max core radius =  0.94 um\n",
-        "\n",
-        " The spot size =  2.26 um\n",
-        "\n",
-        " The divergence angle =  0.221 degree\n",
-        "\n",
-        " The spot size at 50 meter =  5.97 m\n"
-       ]
-      }
-     ],
-     "prompt_number": 25
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example26: PgNo-124"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Initialisation of variables\n",
-      "n1=1.53 # core refractive index\n",
-      "n2=1.50 # cladding  refractive index\n",
-      "y=1.2  # wavelength in um\n",
-      "v=2.405\n",
-      "a=(v*y)/(2*math.pi*(math.sqrt(math.pow(n1,2)-math.pow(n2,2)))) #core radius in micrometer\n",
-      "\n",
-      "print ('%s %.3f %s' %(\" The max diameter= \",2*a,\"um\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The max diameter=  3.047 um\n"
-       ]
-      }
-     ],
-     "prompt_number": 26
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example27: PgNo-127"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "# Initialisation of variables\n",
-      "n1=1.47 # core refractive index\n",
-      "n2=1.46 # cladding  refractive index\n",
-      "y=1.3   # wavelength in um\n",
-      "dl=(n1-n2)/n1 # fractional refractive index diff\n",
-      "\n",
-      "# calculations\n",
-      "NA=math.sqrt(math.pow(n1,2)-math.pow(n2,2))\n",
-      "v=2.405\n",
-      "a=(v*y)/(2*math.pi*(math.sqrt(math.pow(n1,2)-math.pow(n2,2))))# largest core radius in micrometer\n",
-      "n_eff=n1-(NA/(2*math.pi*(a/y))) # fractional refractive index\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The largest core radius = \",a,\"um\"))\n",
-      "print ('%s %.2f' %(\"\\n The fractional refractive index= \",n_eff))\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The largest core radius =  2.91 um\n",
-        "\n",
-        " The fractional refractive index=  1.46\n"
-       ]
-      }
-     ],
-     "prompt_number": 27
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example28: PgNo-130"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# initialisation of variables\n",
-      "n1=1.50 # core refractive index\n",
-      "n2=1.48 # cladding  refractive index\n",
-      "NA=math.sqrt(math.pow(n1,2)-math.pow(n2,2)) # numerical aperture\n",
-      "a=25 # core radius in um\n",
-      "y=0.85 # wavelength in um\n",
-      "v=(2*math.pi*a*NA)/y #cut off parameter\n",
-      "M=math.pow(v,2)/2 # number of modes\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.3f' %(\" The cut off parameter = \",v))\n",
-      "print \"\\n The number of modes = \",int(M)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The cut off parameter =  45.115\n",
-        "\n",
-        " The number of modes =  1017\n"
-       ]
-      }
-     ],
-     "prompt_number": 28
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example29: PgNo-132"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# initialisation of variables\n",
-      "n1=1.50 # core refractive index\n",
-      "a=25    # core radius in um\n",
-      "y=1.5   # wavelength in um\n",
-      "v=2.405\n",
-      "\n",
-      "# Calculations\n",
-      "NA=(v*y)/(2*math.pi*a) # numerical aperture\n",
-      "D=math.pow((NA/n1),2)/(2) # max value of D\n",
-      "n2=n1-(D*n1) # cladding refractive index\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.6f' %(\" The max value of D = \",D))\n",
-      "print ('%s %.2f' %(\"\\n The cladding refractive index = \",n2))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The max value of D =  0.000117\n",
-        "\n",
-        " The cladding refractive index =  1.50\n"
-       ]
-      }
-     ],
-     "prompt_number": 29
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example30: PgNo-133"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "# variable declaration\n",
-      "n1=1.52 #core refractive index\n",
-      "n2=1.48 #cladding  refractive index\n",
-      "a=45    # core radius in um\n",
-      "y=0.85  # wavelength in um\n",
-      "\n",
-      "# Calculations\n",
-      "dl=(n1-n2)/n1 # relative refractive index\n",
-      "x=(math.asin(n2/n1))*(180/math.pi) # critical angle in degree\n",
-      "NA=math.sqrt(math.pow(n1,2)-math.pow(n2,2)) #numerical aperture\n",
-      "a_c=(math.asin(NA))*(180/math.pi) #acceptance angle in degree\n",
-      "a_s=math.pi*(math.pow(n1,2)-math.pow(n2,2))# solid acceptance angle\n",
-      "v=(2*math.pi*a*0.34)/y # normalise v-number\n",
-      "M=math.pow(v,2)/2 # number of guided modes\n",
-      "a1=5 # for single mode step fiber\n",
-      "v1=(2*math.pi*a1*0.34)/y\n",
-      "M1=math.pow(v1,2)/2\n",
-      "R=int(M)-int(M1)# reduction in modes\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.4f' %(\" The max value of D = \",dl))\n",
-      "print ('%s %.2f %s' %(\"\\n The critical angle = \",x,\"degree\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The acceptance angle = \",2*a_c,\"degree\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The solid acceptance angle = \",a_s,\"degree\"))\n",
-      "print ('%s %.2f ' %(\"\\n The numerical aperture = \",NA))\n",
-      "print ('%s %.2f ' %(\"\\n The normalise v-number = \",v))\n",
-      "print \"\\n The number of guided modes = \",int(M)\n",
-      "print \"\\n The reduction in modes = \",R\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The max value of D =  0.0263\n",
-        "\n",
-        " The critical angle =  76.83 degree\n",
-        "\n",
-        " The acceptance angle =  40.54 degree\n",
-        "\n",
-        " The solid acceptance angle =  0.38 degree\n",
-        "\n",
-        " The numerical aperture =  0.35 \n",
-        "\n",
-        " The normalise v-number =  113.10 \n",
-        "\n",
-        " The number of guided modes =  6395\n",
-        "\n",
-        " The reduction in modes =  6317\n"
-       ]
-      }
-     ],
-     "prompt_number": 30
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example31: PgNo-135"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "# Initialisation of variables\n",
-      "\n",
-      "n1=1.46 #core refractive index\n",
-      "a=45/2 #max radius in um\n",
-      "y=0.85 # operating wavelength in um\n",
-      "NA=0.17 # numerical aperture\n",
-      "v=(2*math.pi*a*NA)/y #normalised frequency\n",
-      "M=math.pow(v,2)/2 # number of modes\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f' %(\" The normalised frequency = \",v))\n",
-      "print \"\\n The number of modes = \",int(M)\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The normalised frequency =  27.65\n",
-        "\n",
-        " The number of modes =  382\n"
-       ]
-      }
-     ],
-     "prompt_number": 31
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
-\ No newline at end of file
diff --git a/Optical_Fiber_Communication/Chapter4.ipynb b/Optical_Fiber_Communication/Chapter4.ipynb
deleted file mode 100755
index 5cb4e7c2..00000000
--- a/Optical_Fiber_Communication/Chapter4.ipynb
+++ /dev/null
@@ -1,887 +0,0 @@
-{
- "metadata": {
-  "name": "",
-  "signature": "sha256:7b1c137849cf93f7c696bb48d79752abb9cdb5dcbbc9af1acedb41baab1b64d4"
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 4: Transmission Characteristics of Optical Fibers"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1: PgNo-138"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable initialisation\n",
-      "Pi=100*math.pow(10,-6) # mean optical power in watt\n",
-      "Po=2*math.pow(10,-6) # output mean power in watt\n",
-      "L=6 # length in km\n",
-      "L1=8 # length in km\n",
-      "asp=10*math.log(Pi/Po)/math.log(10) # signal attenuation in dB\n",
-      "as1=asp/L # signal attenuation per km\n",
-      "Li=as1*L1 # Loss incurred along 8 km\n",
-      "Ls=7 # Loss due to splice in dB\n",
-      "as2=Li+Ls #overall signal attenuation in dB\n",
-      "As2=29.4 #aprox. overall signal attenuation in dB\n",
-      "Pio=math.pow(10,(As2/10)) #i/p o/p power ratio\n",
-      "\n",
-      "#Results\n",
-      "print ('%s %.2f %s' %(\" The signal attenuation = \",asp,\"dB\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The signal attenuation per km = \",as1,\"dB/km\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The trgth = \",Li,\"km\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The overall signal attenuation = \",as2,\"dB\"))\n",
-      "print ('%s %.2f' %(\"\\n The i/p o/p power ratio = \", Pio))\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The signal attenuation =  16.99 dB\n",
-        "\n",
-        " The signal attenuation per km =  2.83 dB/km\n",
-        "\n",
-        " The trgth =  22.65 km\n",
-        "\n",
-        " The overall signal attenuation =  29.65 dB\n",
-        "\n",
-        " The i/p o/p power ratio =  870.96\n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2: PgNo-142"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable initialisation\n",
-      "Pi=1.5*math.pow(10,-3) # mean optical power in watt\n",
-      "Po=2*math.pow(10,-6) # output mean power in watt\n",
-      "a=0.5 # dB/km\n",
-      "L=(10*math.log(Pi/Po)/math.log(10))/a # max possible link Length in km\n",
-      "\n",
-      "print ('%s %.3f %s' %(\" The max possible link Length = \",L,\"km\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The max possible link Length =  57.501 km\n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3: PgNo-147"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable Declaration\n",
-      "n=1.46 # core refractive index\n",
-      "p=0.286 # photoelastic coeff\n",
-      "b=7*math.pow(10,-11) # isothermal compressibility\n",
-      "k=1.381*math.pow(10,-23) # boltzmann's constant\n",
-      "tf=1400 # fictive temperature in k\n",
-      "y1=0.85*math.pow(10,-6) # wavelength in m\n",
-      "\n",
-      "# Calculations\n",
-      "yr=((8*math.pow(math.pi,3)*math.pow(n,8)*math.pow(p,2)*(b*k*tf)))/(3*math.pow(y1,4))\n",
-      "akm=pow(math.e,(-yr*math.pow(10,3)))\n",
-      "at=10*math.log(1/akm)/math.log(10)# attenuation at y=0.85 um\n",
-      "y2=1.55*math.pow(10,-6) # wavelength in m\n",
-      "yr1=((8*math.pow(math.pi,3)*math.pow(n,8)*math.pow(p,2)*(b*k*tf)))/(3*math.pow(y2,4))\n",
-      "akm1=math.pow(math.e,(-yr1*math.pow(10,3)))\n",
-      "at1=10*math.log(1/akm1)/math.log(10)# attenuation at y=1.55 um\n",
-      "y3=1.30*math.pow(10,-6) # wavelength in m\n",
-      "yr2=((8*math.pow(math.pi,3)*math.pow(n,8)*math.pow(p,2)*(b*k*tf)))/(3*math.pow(y3,4))\n",
-      "akm2=math.pow(math.e,(-yr2*math.pow(10,3)))\n",
-      "at2=10*math.log(1/akm2)/math.log(10)# attenuation at y=1.30 um\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The Loss of an optical fiber = \",at,\"dB/km\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The Loss of an optical fiber = \",at1,\"dB/km\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The Loss of an optical fiber = \",at2,\"dB/km\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The Loss of an optical fiber =  1.57 dB/km\n",
-        "\n",
-        " The Loss of an optical fiber =  0.14 dB/km\n",
-        "\n",
-        " The Loss of an optical fiber =  0.29 dB/km\n"
-       ]
-      }
-     ],
-     "prompt_number": 3
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 4: PgNo-149"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable declaration\n",
-      "d=6 # core diameter in m\n",
-      "y=1.55 # wavelength in m\n",
-      "a=0.5 # attenuation in dB/km\n",
-      "v=0.4\n",
-      "Pb=4.4*math.pow(10,-3)*math.pow(d,2)*math.pow(y,2)*a*v # threshold power for SBS\n",
-      "Pr=5.9*math.pow(10,-2)*math.pow(d,2)*y*a # threshold power for SRS\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The threshold power for SBS = \",Pb*pow(10,3),\"mw\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The threshold power for SRS = \",Pr,\"W\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The threshold power for SBS =  76.11 mw\n",
-        "\n",
-        " The threshold power for SRS =  1.65 W\n"
-       ]
-      }
-     ],
-     "prompt_number": 4
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5: PgNo-153"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable declaration\n",
-      "n1=1.46     # core refractive index\n",
-      "dl=0.03     # relative refractive index difference\n",
-      "y=0.85*math.pow(10,-6) #operating wavelength in m\n",
-      "a=4*math.pow(10,-6) # core radous in m\n",
-      "\n",
-      "# Calculations\n",
-      "n2=math.sqrt(math.pow(n1,2)-2*dl*math.pow(n1,2)) #cladding refractive index\n",
-      "Rc=(3*math.pow(n1,2)*y)/(4*math.pi*math.pow((math.pow(n1,2)-math.pow(n2,2)),1.5)) # critical radius of curvature for multimode fiber\n",
-      "Dl=0.003    # relative refractive index difference\n",
-      "N2=math.sqrt(math.pow(n1,2)-2*Dl*math.pow(n1,2))\n",
-      "yc=math.pow(2*math.pi*a*n1*(2*Dl),0.5)/2.405 # cut off wavelength in m\n",
-      "y1=1.55*math.pow(10,-6) # operating wavelength in m\n",
-      "Rcs=(20*y1*math.pow((2.748-0.996*(y1/yc)),-3))/math.pow((0.005),1.5) # critical radius of curvature for a single mode fiber\n",
-      "\n",
-      "# Results\n",
-      "print '%s %.4f %s' %(\" The critical radius of curvature for multimode fiber = \",Rc*math.pow(10,6),\"um\")\n",
-      "print '%s %.4f %s' %(\"\\n The critical radius of curvature for a single mode fiber = \",Rcs*math.pow(10,3),\"um\")\n",
-      "print \"\\nThe answer is wrong in the textbook for single mode fiber\""
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The critical radius of curvature for multimode fiber =  9.4569 um\n",
-        "\n",
-        " The critical radius of curvature for a single mode fiber =  4.2620 um\n",
-        "\n",
-        "The answer is wrong in the textbook for single mode fiber\n"
-       ]
-      }
-     ],
-     "prompt_number": 5
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 6: PgNo-157"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# variable declaration\n",
-      "x=2.0 # index profile\n",
-      "dl=0.0126 #index difference\n",
-      "a=(85.0/2.0)*math.pow(10,-6) # core radius\n",
-      "R=2.0*math.pow(10,-3) # curve of radius\n",
-      "n1=1.45 # core refractive index\n",
-      "k=6.28\n",
-      "\n",
-      "# Calculations\n",
-      "y=850.0*math.pow(10,-9) # wavelength in m\n",
-      "A=(x+2)/(2*x*dl)\n",
-      "B=(2*a/R)\n",
-      "C=math.pow((3*y/(2*k*R*n1)),(2.0/3.0))\n",
-      "D=B+C\n",
-      "E=A*D\n",
-      "F=1-E\n",
-      "Lm=-10*math.log(-F)/math.log(10) # macrobend loss in dB\n",
-      "print ('%s %.2f %s' %(\" The macrobend loss = \",Lm,\"dB\"))\n",
-      "print (\"\\n The answer is wrong in the textbook \")"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The macrobend loss =  -3.99 dB\n",
-        "\n",
-        " The answer is wrong in the textbook \n"
-       ]
-      }
-     ],
-     "prompt_number": 6
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 7: PgNO-160"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable initialisation\n",
-      "Pi=15 # optical power in uw\n",
-      "Po=7  # ouput power in uw\n",
-      "L=0.15 # length in km\n",
-      "Ls=(10*math.log(Pi/Po)/math.log(10))/L # Loss of an optical fiber in dB\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The Loss of an optical fiber = \",Ls,\"dB\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The Loss of an optical fiber =  20.07 dB\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 8: PgNo-163"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable initialisation\n",
-      "Pi=200*math.pow(10,-6) # average optical power in watt\n",
-      "Po=5*math.pow(10,-6) # average output power in watt\n",
-      "L=20   # in km\n",
-      "L1=12  # in km\n",
-      "ns=5   # number of attenuation\n",
-      "a=0.9  # attenuation in dB\n",
-      "\n",
-      "# Calculations\n",
-      "sa=10*math.log(Pi/Po)/math.log(10) # signal attenuation\n",
-      "sp=sa/L # signal attenuation per km\n",
-      "sn=sp*L1 # signal attenuation for 12 km\n",
-      "sn1=ns*a # attenuation in dB\n",
-      "sn2=sn+sn1 # overall signal attenuation in dB\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The signal attenuation per km = \",sp,\"dB/km\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The overall signal attenuation= \",sn2,\"dB \"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The signal attenuation per km =  0.80 dB/km\n",
-        "\n",
-        " The overall signal attenuation=  14.11 dB \n"
-       ]
-      }
-     ],
-     "prompt_number": 8
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 9: PgNo-166"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable initialisation\n",
-      "Pi=100*math.pow(10,-6) # average optical power in watt\n",
-      "Po=4*math.pow(10,-6) # average output power in watt\n",
-      "L=6 # in km\n",
-      "L1=10 # in km\n",
-      "\n",
-      "# Calculations\n",
-      "sa=10*math.log(Pi/Po)/math.log(10) # signal attenuation\n",
-      "sp=sa/L # signal attenuation per km\n",
-      "sn=sp*L1 # signal attenuation for 12 km\n",
-      "sn1=sn+9 # overall signal attenuation in dB\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The signal attenuation= \",sa,\"dB\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The signal attenuation per km = \",sp,\"dB/km\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The overall signal attenuation= \",sn1,\"dB\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The signal attenuation=  13.98 dB\n",
-        "\n",
-        " The signal attenuation per km =  2.33 dB/km\n",
-        "\n",
-        " The overall signal attenuation=  32.30 dB\n"
-       ]
-      }
-     ],
-     "prompt_number": 9
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 10: PgNo-167"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# variable initialisation\n",
-      "Pi=20*math.pow(10,-6) #average optical power in watt\n",
-      "Po=7.5*math.pow(10,-6) # average output power in watt\n",
-      "sl=10*math.log(Pi/Po)/math.log(10) # signal Loss in dB\n",
-      "L=15 #in km\n",
-      "L1=30 # in km\n",
-      "ns=29 # number of attenuation\n",
-      "sp=sl/L # signal Loss per km\n",
-      "sn=sp*L1 # signal attenuation for 30 km\n",
-      "sn1=sn+ns # overall signal attenuation in dB\n",
-      "i_o=math.pow(10,(sn1/20)) # input output power ratio\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The signal Loss = \",sl,\"dB\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The signal Loss per km= \",sp,\"dB/km\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The overall signal attenuation= \",sn1,\"dB\"))\n",
-      "print ('%s %.2f' %(\"\\n The input output power ratio= \",i_o))\n",
-      "\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The signal Loss =  4.26 dB\n",
-        "\n",
-        " The signal Loss per km=  0.28 dB/km\n",
-        "\n",
-        " The overall signal attenuation=  37.52 dB\n",
-        "\n",
-        " The input output power ratio=  75.16\n"
-       ]
-      }
-     ],
-     "prompt_number": 10
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11: PgNo-171"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable initialisation\n",
-      "Tf=1400 # temperature in k\n",
-      "Bc=7*math.pow(10,-11) # in m^2/N\n",
-      "n=1.38\n",
-      "P=0.29 # Photoelastic coefficient\n",
-      "y=0.9*math.pow(10,-6) # wavelength in m\n",
-      "K=1.38*math.pow(10,-23) # boltzman's constant\n",
-      "\n",
-      "# Calculations\n",
-      "Rrs=((8*math.pow(math.pi,3)*math.pow(n,8)*math.pow(P,2)*(Bc*Tf*K))/(3*math.pow(y,4)))\n",
-      "Rrs1=Rrs/math.pow(10,-3) # per km\n",
-      "Lkm=math.pow(math.e,(-Rrs1)) # transmission loss facter\n",
-      "At=10*math.log(1/Lkm)/math.log(10) # Attenuation in dB/km\n",
-      "\n",
-      "# results\n",
-      "print ('%s %.2f %s' %(\" The Attenuation= \",At,\"dB/km\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The Attenuation=  0.82 dB/km\n"
-       ]
-      }
-     ],
-     "prompt_number": 11
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 12: PgNo-172"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable initialisation\n",
-      "y=1.35 # wavelength in um\n",
-      "d=5 # core diamater in um\n",
-      "a=0.75 # attenuation in dB/km\n",
-      "v=0.45 # bandwidth in GHz\n",
-      "\n",
-      "# calculations\n",
-      "Pb=4.4*math.pow(10,-3)*math.pow(d,2)*math.pow(y,2)*(a*v) #threshold optical power for sbs\n",
-      "Pr=5.9*math.pow(10,-2)*math.pow(d,2)*(y)*(a) #threshold optical power for sbr\n",
-      "Pbr=Pb/Pr # the ratio of threshold power level\n",
-      "print ('%s %.2f %s' %(\" The ratio of threshold power level= \",Pbr*100,\"%\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The ratio of threshold power level=  4.53 %\n"
-       ]
-      }
-     ],
-     "prompt_number": 12
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 13: PgNo-175"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable initialisation\n",
-      "n1=1.5 #core refractive index\n",
-      "y=0.85*math.pow(10,-6) # wavelength in m\n",
-      "dl=0.024 # relative refractive index difference\n",
-      "N2=math.sqrt(math.pow(n1,2)-2*dl*math.pow(n1,2)) # cladding refractive index\n",
-      "n2=1.46\n",
-      "Rcs=(3*math.pow(n1,2)*y)/((4*math.pi)*math.pow((math.pow(n1,2)-math.pow(n2,2)),1.5)) # critical radius of curvature for multimode fiber\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.3f %s' %(\" The critical radius of curvature = \",Rcs*pow(10,6),\"um\"))\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The critical radius of curvature =  11.207 um\n"
-       ]
-      }
-     ],
-     "prompt_number": 13
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14: PgNo-177"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable initialisation\n",
-      "n1=1.45 # core refractive index\n",
-      "y=1.5*math.pow(10,-6) # wavelength in m\n",
-      "dl=0.03 # relative refractive index difference\n",
-      "a=5.0*math.pow(10,-6) # core radius\n",
-      "n2=math.sqrt(math.pow(n1,2)-2*dl*math.pow(n1,2)) # cladding refractive index\n",
-      "yc=(2*math.pi*a*n1*math.sqrt(2*dl))/(2.405)\n",
-      "Rcs=(20.0*y*(2.748-0.996*math.pow((y/yc),-3)))/math.pow((math.pow(n1,2)-math.pow(n2,2)),1.5)#critical radius of curvature for single mode fiber\n",
-      "Rcs1=(3*math.pow(n1,2)*y)/((4*math.pi)*math.pow(math.pow(n1,2)-math.pow(n2,2),1.5)) # critical radius of curvature for multimode fiber\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The critical radius of curvature for single mode fiber = \",Rcs*pow(10,6),\"um\"))\n",
-      "print (\"\\n The answer is wrong in the textbook \")\n",
-      "print ('%s %.2f %s' %(\"\\n The critical radius of curvature for multimode fiber = \",Rcs1*pow(10,6),\"um\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The critical radius of curvature for single mode fiber =  -17893.87 um\n",
-        "\n",
-        " The answer is wrong in the textbook \n",
-        "\n",
-        " The critical radius of curvature for multimode fiber =  16.80 um\n"
-       ]
-      }
-     ],
-     "prompt_number": 14
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 15: PgNo-179"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# variable declaration\n",
-      "L=500.0/1000.0 # distance in km\n",
-      "Pio=(1/(1-0.75))\n",
-      "Ls=10*math.log(Pio)/math.log(10)/L # Loss in dB/km\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.3f %s' %(\" The Loss = \",Ls,\"dB/km\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The Loss =  12.041 dB/km\n"
-       ]
-      }
-     ],
-     "prompt_number": 15
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 16: PgNo-181"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable initialisation\n",
-      "L=5 # length in km\n",
-      "a=0.5 # attenuaion loss in dB/km\n",
-      "# Calculations\n",
-      "Po=math.pow(10,-3)*math.pow(10,(-(a*L)/10)) # power level in mW\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.3f %s' %(\" The power level = \",Po*pow(10,3),\"mW\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The power level =  0.562 mW\n"
-       ]
-      }
-     ],
-     "prompt_number": 16
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 17: PgNo-186"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable initialisation\n",
-      "L=1 #distance in km\n",
-      "Pio=(1/(1-0.40))\n",
-      "# Calculations\n",
-      "Ls=10*math.log(Pio)/math.log(10)/L # Loss in dB/km\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.3f %s' %(\" The Loss = \",Ls,\"dB/km\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The Loss =  2.218 dB/km\n"
-       ]
-      }
-     ],
-     "prompt_number": 17
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 18: PgNo-188"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Initialisation of variables\n",
-      "Pi=1*math.pow(10,-3) # input power in watt\n",
-      "Po=0.75*math.pow(10,-3) # output power in watt\n",
-      "a=0.5 #in dB/km\n",
-      "L=(10*math.log(Pi/Po)/math.log(10))/a # transmission length in km\n",
-      "\n",
-      "print ('%s %.1f %s'%(\" The transmission length = \",L,\"km\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The transmission length =  2.5 km\n"
-       ]
-      }
-     ],
-     "prompt_number": 18
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 19: PgNo-189"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# variable initialisation\n",
-      "y=1300.0*math.pow(10,-9) # wavelemgth in m\n",
-      "yc=1200.0*math.pow(10,-9) # cut off wavelength in m\n",
-      "rc=5.0*math.pow(10,-6) #core diameter in m\n",
-      "n=1.5 #refractive index\n",
-      "R=1.2/100.0 # curve of radius in m\n",
-      "\n",
-      "# Calculations\n",
-      "dmf=2*rc*((0.65)+0.434*math.pow((y/yc),1.5)+0.0149*math.pow((y/yc),6)) # mode field diameter\n",
-      "K=(2.0*math.pi)/y\n",
-      "Lm=-10*math.log(-1*(1-math.pow(K,4)*math.pow(n,4)*math.pow(((3.95*math.pow(10,-6))/(8*math.pow(R,2))),6)))/math.log(10) # macrobend loss\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The mode field diameter = \",dmf*pow(10,6),\"um\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The macrobend loss = \",Lm,\"dB\"))\n",
-      "print (\"\\n The answer is wrong in the textbook\")\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The mode field diameter =  11.63 um\n",
-        "\n",
-        " The macrobend loss =  -126.52 dB\n",
-        "\n",
-        " The answer is wrong in the textbook\n"
-       ]
-      }
-     ],
-     "prompt_number": 19
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 20: PgNO-191"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "#Variable initialisation\n",
-      "Pi=10*math.pow(10,-3) # input power in watt\n",
-      "Po=8*math.pow(10,-3)  # output power in watt\n",
-      "L=0.150     # length in km\n",
-      "Ls=(10*math.log(Po/Pi)/math.log(10))/L\n",
-      "\n",
-      "print ('%s %.2f %s' %(\" The transmission length = \",Ls,\"km\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The transmission length =  -6.46 km\n"
-       ]
-      }
-     ],
-     "prompt_number": 20
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
-\ No newline at end of file
diff --git a/Optical_Fiber_Communication/Chapter5.ipynb b/Optical_Fiber_Communication/Chapter5.ipynb
deleted file mode 100755
index d4366624..00000000
--- a/Optical_Fiber_Communication/Chapter5.ipynb
+++ /dev/null
@@ -1,1476 +0,0 @@
-{
- "metadata": {
-  "name": "",
-  "signature": "sha256:9df1a39eaf45bb37d3874de747aedcb050a5a7704427c92544b1342299e9f172"
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 5 : Optical Sources Laser"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1: PgNo-193"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# variable declaration\n",
-      "t=0.1*math.pow(10,-6) # pulse broading in sec\n",
-      "d=12 # disance in km\n",
-      "B=1/(2*t) # max bandwidth MHz\n",
-      "\n",
-      "# Calculations\n",
-      "ds=t/d #dispersion in ns/km\n",
-      "bl=B*d # bandwidth length product\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.1f %s' %(\" The max bandwidth = \",B/pow(10,6),\"MHz\"))\n",
-      "print ('%s %.3f %s' %(\"\\n The dispersion = \",ds*pow(10,9),\"ns/km\"))\n",
-      "print ('%s %.1f %s' %(\"\\n bandwidth length product = \",bl/pow(10,6),\"MHz km\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The max bandwidth =  5.0 MHz\n",
-        "\n",
-        " The dispersion =  8.333 ns/km\n",
-        "\n",
-        " bandwidth length product =  60.0 MHz km\n"
-       ]
-      }
-     ],
-     "prompt_number": 65
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2: PgNo-194"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "# Variable initialisation\n",
-      "t=0.1*math.pow(10,-6) # pulse broadening in sec\n",
-      "d=15 # disance in km\n",
-      "B=1/(2*t) # max bandwidth MHz\n",
-      "ds=t/d # dispersion in ns/km\n",
-      "bl=B*d # bandwidth length product\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.1f %s' %(\" The max bandwidth = \",B/pow(10,6),\"MHz\"))\n",
-      "print ('%s %.3f %s' %(\"\\n The dispersion = \",ds*pow(10,9),\"ns/km\"))\n",
-      "print ('%s %.1f %s' %(\"\\n bandwidth length product = \",bl/pow(10,6),\"MHz km\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The max bandwidth =  5.0 MHz\n",
-        "\n",
-        " The dispersion =  6.667 ns/km\n",
-        "\n",
-        " bandwidth length product =  75.0 MHz km\n"
-       ]
-      }
-     ],
-     "prompt_number": 66
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3: PgNo-197"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable declaration\n",
-      "n1=1.465 # core refractive index\n",
-      "n2=1.45 #cladding refractive index\n",
-      "c=3*math.pow(10,8) # the speed of light in m/s\n",
-      "NA=math.sqrt(math.pow(n1,2)-math.pow(n2,2)) # numerical aperture\n",
-      "Mp=math.pow(NA,2)/(2*n1*c) # multipath pulse broadening in ns/km\n",
-      "bl=(1/math.pow(NA,2))*(2*n1*c) # bandwidth length product in GHz km\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f' %(\" The numerical aperture = \", NA))\n",
-      "print ('%s %.2f %s' %(\"\\n The multipath pulse broadening = \",Mp*pow(10,9),\"ns/km\"))\n",
-      "print ('%s %.1f %s' %(\"\\n The bandwidth length product = \",bl/pow(10,9),\"GHz km\"))\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The numerical aperture =  0.21\n",
-        "\n",
-        " The multipath pulse broadening =  0.05 ns/km\n",
-        "\n",
-        " The bandwidth length product =  20.1 GHz km\n"
-       ]
-      }
-     ],
-     "prompt_number": 67
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 4: PgNo-199"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable declaration\n",
-      "ds=0.020 # material dispersion\n",
-      "c=3*math.pow(10,8) # the speed of light m/s\n",
-      "y=1.3  #wavelength in um\n",
-      "M=ds/(c*y) # material dispersion parameter in ps/nm/km\n",
-      "w=6 # spectral width in nm\n",
-      "l=1 # length in km\n",
-      "rm=w*l*M # rms pulse broadening in ns/km\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The material dispersion parameter = \",M*math.pow(10,12),\"ps/nm/km\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The rms pulse broadening = \",rm*math.pow(10,9),\"ns/km\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The material dispersion parameter =  51.28 ps/nm/km\n",
-        "\n",
-        " The rms pulse broadening =  0.31 ns/km\n"
-       ]
-      }
-     ],
-     "prompt_number": 68
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5: PgNo-201"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable initialisation\n",
-      "wr=0.0014   # relative spectral width in nm\n",
-      "y=1.3*math.pow(10,-6)    # wavelength in m\n",
-      "w=wr*y      # spectral width in nm\n",
-      "ds=0.020    # material dispersion\n",
-      "c=3*math.pow(10,8) # the speed of light in m/s\n",
-      "M=ds/(c*y)  # material dispersion parameter in ps/nm/km\n",
-      "l=1         # length in km\n",
-      "rm=w*l*M    # rms pulse broadening in ns/km\n",
-      "\n",
-      "print ('%s %.3f %s' %(\" The rms pulse broadening = \",rm*pow(10,9)*pow(10,3),\"ns/km\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The rms pulse broadening =  0.093 ns/km\n"
-       ]
-      }
-     ],
-     "prompt_number": 69
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 6: PgNo-205"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Initialisation of variables\n",
-      "n1=1.46 # core refractive index\n",
-      "dl=0.01 # relative index difference\n",
-      "L=10*math.pow(10,3) # optical length in meter\n",
-      "c=3*math.pow(10,8)  # the speed of light in m/s\n",
-      "\n",
-      "# calculations\n",
-      "dt=(L*n1*dl)/c #delay difference in s\n",
-      "dT=dt*math.pow(10,9)  # delay difference in ns\n",
-      "rm=(L*n1*dl)/(2*math.sqrt(3)*c) # rms pulse broadening s\n",
-      "rM=rm*math.pow(10,9) # rms pulse broadening ns\n",
-      "bt=0.2/rm # max bit rate in bit/sec\n",
-      "bT=bt/math.pow(10,6) # max bit rate in M bits/sec\n",
-      "bl=bt*L # bandwidth length product in Hz meter\n",
-      "bL=(bt*L)/(math.pow(10,6)*math.pow(10,3))  #bandwidth length product in MHz km\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The delay difference = \",dT,\"ns\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The rms pulse broadening = \",rM,\"ns\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The max bit rate = \",bT,\"M bits/sec\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The bandwidth length product = \",bL,\"MHz km\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The delay difference =  486.67 ns\n",
-        "\n",
-        " The rms pulse broadening =  140.49 ns\n",
-        "\n",
-        " The max bit rate =  1.42 M bits/sec\n",
-        "\n",
-        " The bandwidth length product =  14.24 MHz km\n"
-       ]
-      }
-     ],
-     "prompt_number": 70
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 7: PgNo-208"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable declaration\n",
-      "n1=1.5 # core refractive index\n",
-      "dl=0.01 # relative index difference\n",
-      "L=6*math.pow(10,3) # optical length in meter\n",
-      "c=3*math.pow(10,8) # the speed of light in m/s\n",
-      "\n",
-      "# calculations\n",
-      "rm=(L*n1*dl)/(2*math.sqrt(3)*c) # rms pulse broadening s\n",
-      "rM=rm*math.pow(10,9) # rms pulse broadening ns\n",
-      "bt=0.2/rm # max bit rate in bit/sec\n",
-      "bT=bt/math.pow(10,6) # max bit rate in M bits/sec\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The rms pulse broadening = \",rM,\"ns\"))\n",
-      "print ('%s %.4f %s' %(\"\\n The max bit rate = \",bT,\"M bits/sec\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The rms pulse broadening =  86.60 ns\n",
-        "\n",
-        " The max bit rate =  2.3094 M bits/sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 71
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 8: PgNo-209"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable declaration\n",
-      "n1=1.4  # core refractive index\n",
-      "dl=0.012 # relative index difference\n",
-      "L=6*math.pow(10,3) # optical length in meter\n",
-      "c=3*math.pow(10,8) # the speed of light in m/s\n",
-      "\n",
-      "# Calculations\n",
-      "dt=(L*n1*dl)/c # delay difference in s\n",
-      "dT=dt*math.pow(10,9) # delay difference in ns\n",
-      "rm=(L*n1*dl)/(2*math.sqrt(3)*c) # rms pulse broadening s\n",
-      "rM=rm*math.pow(10,9) # rms pulse broadening ns\n",
-      "bt=0.2/rm # max bit rate in bit/sec\n",
-      "bT=bt/math.pow(10,6) # max bit rate in M bits/sec\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.f %s' %(\" The delay difference = \",dT,\"ns\"))\n",
-      "print ('%s %.1f %s' %(\"\\n The rms pulse broadening = \",rM,\"ns\"))\n",
-      "print ('%s %.3f %s' %(\"\\n The max bit rate = \",bT,\"M bits/sec\"))\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The delay difference =  336 ns\n",
-        "\n",
-        " The rms pulse broadening =  97.0 ns\n",
-        "\n",
-        " The max bit rate =  2.062 M bits/sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 72
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 9: PgNo-211"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# variable initialisation\n",
-      "n1=1.5 #core refractive index\n",
-      "c=3*math.pow(10,8) # the speed of light m/s\n",
-      "w=6*math.pow(10,-6) # rms spectral width in m\n",
-      "M=200   # material dispersion parameter in ps/nm/km\n",
-      "NA=0.25 # numerical aperture\n",
-      "w=50   # spectral width in nm\n",
-      "L=1    # length in m\n",
-      "\n",
-      "# calculations\n",
-      "rm=w*L*M # rms pulse broadening in s/km\n",
-      "rM=rm/math.pow(10,3) # rms pulse broadening in ns/km due to material dispersion\n",
-      "rm1=(L*1000*math.pow((NA),2))/(4*math.sqrt(3)*n1*c) # rms pulse broadening in ns/km due to material dispersion in sec/m\n",
-      "rM1=rm1*math.pow(10,9) # rms pulse broadening in ns/km due to intermodel dispersion in ns/km\n",
-      "rmt=math.sqrt(math.pow(rM,2)+math.pow(rM1,2)) # total rms pulse broadening in ns/km\n",
-      "bl=0.2/(rmt*math.pow(10,-9)) # bandwidth length product in Hz km\n",
-      "bL=bl/math.pow(10,6) # bandwidth length product in MHz km\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The total rms pulse broadening = \",rmt,\"ns/km\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The bandwidth length product = \",bL,\"MHz km\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The total rms pulse broadening =  22.40 ns/km\n",
-        "\n",
-        " The bandwidth length product =  8.93 MHz km\n"
-       ]
-      }
-     ],
-     "prompt_number": 73
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 10: PgNo-214"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable declaration\n",
-      "yo=1320.0 # zero dispersion wavelength in nm\n",
-      "y=1290.0  # dispersion wavelength in nm\n",
-      "so=0.092 # dispersion slop\n",
-      "dt=(y*so/4)*(1-math.pow((yo/y),4)) #toal first order dispersion at 1290 nm in ps/nm/km\n",
-      "yo1=1310.0 # zero dispersion wavelength in um\n",
-      "y1=1550.0  # dispersion wavelength in nm\n",
-      "so=0.092 # dispersion slope\n",
-      "dt1=(y1*so/4)*(1-math.pow((yo1/y1),4)) # toal first order dispersion at 1550 nm in ps/nm/km\n",
-      "DM=13.5 # profile dispersion in ps/nm/km\n",
-      "DP=0.4  # profile dispersion in ps/nm/km\n",
-      "DW=dt1-(DM+DP) # wavelength dispersion in ps/nm/km\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The total first order dispersion at 1290 nm = \",dt,\"ps/nm/km\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The total first order dispersion at 1550 nm = \",dt1,\"ps/nm/km\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The wavelength dispersion at 1550 nm = \",DW,\"ps/nm/km\"))\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The total first order dispersion at 1290 nm =  -2.86 ps/nm/km\n",
-        "\n",
-        " The total first order dispersion at 1550 nm =  17.46 ps/nm/km\n",
-        "\n",
-        " The wavelength dispersion at 1550 nm =  3.56 ps/nm/km\n"
-       ]
-      }
-     ],
-     "prompt_number": 74
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11: PgNo-218"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# variable declaration\n",
-      "L=6*math.pow(10,-2) # beat length in m\n",
-      "dy=6*math.pow(10,-9) # spectral width in m\n",
-      "y=1.3*math.pow(10,-6) # operating wavelength in m\n",
-      "\n",
-      "# Calculations\n",
-      "BF=y/(L) # model birefrigence in um\n",
-      "Lc=math.pow(y,2)/(BF*dy) # coherence length in m\n",
-      "db=2*math.pi/(L) #difference beween two propagation constants\n",
-      "dB=(2*math.pi*BF)/y\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The model birefrigence = \",BF*pow(10,6),\"um\"))\n",
-      "print ('%s %.1f %s' %(\"\\n The coherence length= \",Lc,\"m\"))\n",
-      "print ('%s %.2f' %(\"\\n The difference beween two propagation constants= \", db))\n",
-      "print ('%s %.2f' %(\"\\n The difference beween two propagation constants= \", dB))\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The model birefrigence =  21.67 um\n",
-        "\n",
-        " The coherence length=  13.0 m\n",
-        "\n",
-        " The difference beween two propagation constants=  104.72\n",
-        "\n",
-        " The difference beween two propagation constants=  104.72\n"
-       ]
-      }
-     ],
-     "prompt_number": 75
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 12: PgNo-219"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable initialisation\n",
-      "y=0.85*math.pow(10,-6) # operating wavelength in m\n",
-      "L=0.5*math.pow(10,-3) # beat length in m\n",
-      "BF=y/(L) # model birefrigence in um\n",
-      "L1=75 # beat length in m\n",
-      "BF1=y/(L1) #model birefrigence in um\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.4f %s' %(\" The model birefrigenceat 0.5 nm = \",BF,\"*10^-3\"))\n",
-      "print ('%s %.3f %s' %(\"\\n The model birefrigence at 75 m = \",BF1*math.pow(10,8),\"*10^-8\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The model birefrigenceat 0.5 nm =  0.0017 *10^-3\n",
-        "\n",
-        " The model birefrigence at 75 m =  1.133 *10^-8\n"
-       ]
-      }
-     ],
-     "prompt_number": 76
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 13: PgNo-222"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable declaration\n",
-      "Lc=100000 # coherence length in m\n",
-      "y=1.32*math.pow(10,-6) # operating wavelength in m\n",
-      "dy=1.5*math.pow(10,-9) # spectral width in m\n",
-      "BF=math.pow(y,2)/(Lc*dy) # model birefrigence in um\n",
-      "L=y/BF # beat length in m\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The beat length= \",L,\"m\"))\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The beat length=  113.64 m\n"
-       ]
-      }
-     ],
-     "prompt_number": 77
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14: PgNo-225"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "#Variable initialisation\n",
-      "n1=1.46 # core refractive index\n",
-      "NA=0.25 # numerical aperture\n",
-      "c=3*math.pow(10,5) # the speed of light km/s\n",
-      "L=7  # length in km\n",
-      "si=math.pow(NA,2)/(4*math.sqrt(3)*n1*c) # intermodel pulse broadening ns/km\n",
-      "st=si*L # total intermodel pulse broadening\n",
-      "BW=0.187/st # bandwidth in MHz\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The intermodel pulse broadening = \",st*math.pow(10,9),\"ns/km\"))\n",
-      "print ('%s %.4f %s' %(\"\\n The bandwidth = \",BW/math.pow(10,6),\"MHz\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The intermodel pulse broadening =  144.17 ns/km\n",
-        "\n",
-        " The bandwidth =  1.2971 MHz\n"
-       ]
-      }
-     ],
-     "prompt_number": 78
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 15: PgNo-227"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable initialisation\n",
-      "n1=1.46 # core refractive index\n",
-      "df=0.025\n",
-      "L=500 # length in m\n",
-      "c=3*math.pow(10,8) # the speed of light in m/s\n",
-      "dt=(n1*L*math.pow(df,2))/(8*c) # max dispersion in ns/m\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.4f %s' %(\" The  max dispersion = \",dt*math.pow(10,9),\"ns/m\"))\n",
-      "print (\"\\n The answer in the textbook is wrong \")"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The  max dispersion =  0.1901 ns/m\n",
-        "\n",
-        " The answer in the textbook is wrong \n"
-       ]
-      }
-     ],
-     "prompt_number": 79
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 16: PgNo-229"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable initialisation\n",
-      "dy=15 # spectral width in nm\n",
-      "L=25 # optical length in km\n",
-      "ps=1.60 #pulse spreads in ns/km\n",
-      "pS=1.6 # pulse spreads in ns/km\n",
-      "d=pS/(dy*L) # material dispersion in ns/km^2/nm\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.4f %s' %(\" The  max dispersion = \",d,\"ns/km^2/nm\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The  max dispersion =  0.0043 ns/km^2/nm\n"
-       ]
-      }
-     ],
-     "prompt_number": 80
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 17: PgNo-231"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "#Variable declaration\n",
-      "n1=1.46 # core refractive index\n",
-      "NA=0.2 # numerical aperture\n",
-      "L=1.5*math.pow(10,3) # length in m\n",
-      "c=3*math.pow(10,8) # the spee of light in m/s\n",
-      "dt=(L*math.pow(NA,2))/(2*c*n1) #intermodel dispersion in ns/km\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.3f %s' %(\" The intermodel dispersion = \",dt*math.pow(10,9),\"ns/km\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The intermodel dispersion =  68.493 ns/km\n"
-       ]
-      }
-     ],
-     "prompt_number": 81
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 18: PgNo-234"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# variable initialisation\n",
-      "BLP=250*math.pow(10,6) # bandwidth length product in Hz\n",
-      "tr=0.32/BLP  # intermodel pulse width broadening\n",
-      "md=75    # material dispersion in ps/nm.km\n",
-      "tm=2.25  # pulse broadening due to material dispersion in ns/km\n",
-      "tc=math.sqrt(math.pow((tr*math.pow(10,9)),2)+math.pow(tm,2)) # combine pulse broadening in ns/km\n",
-      "Ba=0.32/tm*math.pow(10,9)  # actual BLP in Hz.km\n",
-      "Bac=Ba/math.pow(10,6) # actual BLP in MHz.km\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The intermodel pulse width broadening = \",tr*pow(10,9),\"ns/km\"))\n",
-      "print ('%s %.2f %s' %(\"\\n pulse broadening due to material dispersion = \",tm,\"ns/km\"))\n",
-      "print ('%s %.4f %s' %(\"\\n The combine pulse broadening = \",tc,\"ns/km\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The actual BLP = \",Bac,\"MHz.km\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The intermodel pulse width broadening =  1.28 ns/km\n",
-        "\n",
-        " pulse broadening due to material dispersion =  2.25 ns/km\n",
-        "\n",
-        " The combine pulse broadening =  2.5886 ns/km\n",
-        "\n",
-        " The actual BLP =  142.22 MHz.km\n"
-       ]
-      }
-     ],
-     "prompt_number": 82
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 19: PgNo-235"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable declaration\n",
-      "L=40 # length in m\n",
-      "Ny=.75 # in ps/nm\n",
-      "dy=8  # spectral width in nm\n",
-      "t_mat=L*Ny*dy  # chromatic/material dispersion in ps\n",
-      "t_mat1=t_mat/1000 # chromatic/material dispersion in ns\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The chromatic/material dispersion = \",t_mat1,\"ns\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The chromatic/material dispersion =  0.24 ns\n"
-       ]
-      }
-     ],
-     "prompt_number": 83
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 20: PgNo-237"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable initialisation\n",
-      "y=1.3 # operating wavelength in um\n",
-      "md=2.80 # material dispersion in ns\n",
-      "wd=0.50 # waveguide dispersion in ns\n",
-      "wt=0.60 # width of transmitted pulse in ns\n",
-      "\n",
-      "# Calculations\n",
-      "td=math.sqrt(math.pow(md,2)+math.pow(wd,2)) # total dispersion in ns\n",
-      "dt=wt+td  # received pulse width in ns\n",
-      "br=1/(5*dt*math.pow(10,-9)) # max bit rate bit/sec\n",
-      "Br=br/math.pow(10,6) # max bit rate in mbps\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.4f %s' %(\" The received pulse width = \",dt,\"ns\"))\n",
-      "print ('%s %.4f %s' %(\"\\n The  max bit rate = \",Br,\"mbps\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The received pulse width =  3.4443 ns\n",
-        "\n",
-        " The  max bit rate =  58.0671 mbps\n"
-       ]
-      }
-     ],
-     "prompt_number": 84
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 21: PgNo-239"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable declaration\n",
-      "y=0.85  #  operating wavelength in um\n",
-      "md=2.75 # material dispersion in ns\n",
-      "wd=0.45 # waveguide dispersion in ns\n",
-      "wt=0.50 # width of transmitted pulse in ns\n",
-      "\n",
-      "# Calculations\n",
-      "td=math.sqrt(math.pow(md,2)+math.pow(wd,2)) # total dispersion in ns\n",
-      "dt=wt+td # received pulse width in ns\n",
-      "br=1/(5*dt*math.pow(10,-9)) # max bit rate bit/sec\n",
-      "Br=br/math.pow(10,6) # max bit rate in mbps\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.4f %s' %(\" The received pulse width = \",dt,\"ns\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The  max bit rate = \",Br,\"mbps\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The received pulse width =  3.2866 ns\n",
-        "\n",
-        " The  max bit rate =  60.85 mbps\n"
-       ]
-      }
-     ],
-     "prompt_number": 85
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 22: PgNo-241"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable initialisation\n",
-      "n1=1.46 #  core refractive index\n",
-      "df=0.025\n",
-      "L=1500 # length in meter\n",
-      "c=3*math.pow(10,8) # the speed of ligth in m/s\n",
-      "md=(n1*L*df)/(c*(1-df)) # max dispersion in sec\n",
-      "Md=md*math.pow(10,9) # max dispersion in ns\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The max dispersion = \",Md,\"ns\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The max dispersion =  187.18 ns\n"
-       ]
-      }
-     ],
-     "prompt_number": 86
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 23: PgNo-243"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable initialisation\n",
-      "n1=1.5 #  core refractive index\n",
-      "L=1000 # length in meter\n",
-      "NA=0.22 # numerical aperture\n",
-      "\n",
-      "# Calculations\n",
-      "dl=math.pow((NA/n1),2)/2;\n",
-      "c=3*math.pow(10,8) # the speed of ligth in m/s\n",
-      "dt=(L*n1*dl)/c #intermodel dispersion in sec\n",
-      "dT=dt*math.pow(10,9) # intermodel dispersion in ns\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The max dispersion = \",dT,\"ns\"))\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The max dispersion =  53.78 ns\n"
-       ]
-      }
-     ],
-     "prompt_number": 87
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 24: PgNo-246"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable declaration\n",
-      "w=30.0 #  line width in nm\n",
-      "L=1.5 # length in km\n",
-      "d1=6.0  # in ns/km\n",
-      "d2=85.0 # in ps/km/nm\n",
-      "d3=d2/1000 # in ns/km/nm\n",
-      "dt=d1*L # intermodel dispersion in ns\n",
-      "dt1=w*d3*L # intramodel dispersion in ns\n",
-      "dT=math.sqrt(math.pow(dt,2)+math.pow(dt1,2)) # total dispersion in ns\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.1f %s' %(\" The max dispersion = \",dt,\"ns\"))\n",
-      "print ('%s %.3f %s' %(\"\\n The max dispersion = \",dt1,\"ns\"))\n",
-      "print ('%s %.3f %s' %(\"\\n The max dispersion = \",dT,\"ns\"))\n",
-      "print (\"\\n answer in the textbook is wrong \")"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The max dispersion =  9.0 ns\n",
-        "\n",
-        " The max dispersion =  3.825 ns\n",
-        "\n",
-        " The max dispersion =  9.779 ns\n",
-        "\n",
-        " answer in the textbook is wrong \n"
-       ]
-      }
-     ],
-     "prompt_number": 88
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 25: PgNo-248"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable initialisation\n",
-      "n1=1.55  # core refractive index\n",
-      "n2=1.48  # cladding refractive index\n",
-      "l=150   # fiber length in m\n",
-      "c=3*math.pow(10,8) #the speed of light in m/s\n",
-      "\n",
-      "# calculations\n",
-      "dl=(math.pow(n1,2)-math.pow(n2,2))/(2*n1)\n",
-      "dL=0.068\n",
-      "dt=(l*n1*dL)/(c) # intermodel dispersion in s\n",
-      "dT=dt*math.pow(10,9) # intermodel dispersion in ns\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The intermodel dispersion = \",dT,\"ns\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The intermodel dispersion =  52.70 ns\n"
-       ]
-      }
-     ],
-     "prompt_number": 89
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 26: PgNo-249"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Initialisation of variables\n",
-      "n1=1.42 # core refractive index\n",
-      "dl=0.02\n",
-      "c=3*math.pow(10,8) # the speed of light in m/s\n",
-      "dt=(n1*dl)/c # intermodel disersion in sec/m\n",
-      "dt1=dt*1000 # intermodel disersion in sec/km\n",
-      "dt2=dt1*math.pow(10,9) # intermodel disersion in ns/km\n",
-      "# Results\n",
-      "print ('%s %.3f %s' %(\" The intermodel dispersion per km = \",dt2,\"ns/km\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The intermodel dispersion per km =  94.667 ns/km\n"
-       ]
-      }
-     ],
-     "prompt_number": 90
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 27: PgNo-251"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "# Results\n",
-      "print (\" Dwg=n2*(dl/cy)*V(d^2(Vb)/dV^2)\")\n",
-      "print (\"\\n Dwg=n2*(dl/cy)*V(d^2(V(1-exp(-V))))/dv^2\")\n",
-      "print (\"\\n =CV(Z-V)exp(-V)\")\n",
-      "print (\"\\n where C=n2(dl/cy)\")\n",
-      "print (\"\\n waveguide dispersion will be zero , when V=2\")"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " Dwg=n2*(dl/cy)*V(d^2(Vb)/dV^2)\n",
-        "\n",
-        " Dwg=n2*(dl/cy)*V(d^2(V(1-exp(-V))))/dv^2\n",
-        "\n",
-        " =CV(Z-V)exp(-V)\n",
-        "\n",
-        " where C=n2(dl/cy)\n",
-        "\n",
-        " waveguide dispersion will be zero , when V=2\n"
-       ]
-      }
-     ],
-     "prompt_number": 91
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 28: PgNo-255"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# variable initialisation\n",
-      "y=900.0   # operating wavelength in nm\n",
-      "yo=1343.0 # wavelength in nm\n",
-      "so=0.095 # in ps/nm^2-km\n",
-      "L=150.0  #  in km\n",
-      "dy=50.0  # in nm\n",
-      "\n",
-      "# calculations\n",
-      "Dy=(so*y/4)*(1-math.pow((yo/y),4)) # inps/nm-km\n",
-      "Dy1=Dy*(-1) # do not consider -ve sign\n",
-      "dt=Dy1*L*dy # pulse spreading in ps\n",
-      "dt1=dt/1000 # pulse spreading in ns\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.3f %s' %(\" The pulse spreading = \",dt1,\"ns\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The pulse spreading =  634.567 ns\n"
-       ]
-      }
-     ],
-     "prompt_number": 92
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 29: PgNo-260"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Initialisation of variables\n",
-      "n1=1.48 #  core refractive index\n",
-      "y=900  # operating wavelength in nm\n",
-      "yo=1343 # wavelength in nm\n",
-      "so=0.095 # in ps/nm^2-km\n",
-      "L=1.5 # in km\n",
-      "dy=50 # in nm\n",
-      "dl=0.002\n",
-      "c=3*math.pow(10,8) # the speed of ligth in m/s\n",
-      "\n",
-      "# calculations\n",
-      "Dm=(so*y/4)*(1-math.pow((yo/y),4))# inps/nm-km\n",
-      "Dm1=Dm*(-1) # do not consider -ve sign\n",
-      "Vd=0.26\n",
-      "Dw=((n1*dl)/(c*y*math.pow(10,-9)))*(Vd);\n",
-      "DW=Dw*math.pow(10,6)# in ps/nm-km\n",
-      "dt=DW*L*dy #  pulse spreading in ps\n",
-      "dt1=dt/100 # pulse spreading in ns\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.4f %s' %(\" The pulse spreading = \",dt1,\"ps\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The pulse spreading =  2.1378 ps\n"
-       ]
-      }
-     ],
-     "prompt_number": 93
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 30: PgNo-263"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Initialisation of variables\n",
-      "a=4.1*math.pow(10,-6) # core radius in um\n",
-      "dl=0.0036\n",
-      "y1=1.310*math.pow(10,-6) # operating wavelength in um\n",
-      "y2=1.550*math.pow(10,-6)# operating wavelength in um\n",
-      "n1=1.4677# core refrative index at y=1.310\n",
-      "n2=1.4682# core refrative index at y=1.550\n",
-      "\n",
-      "# Calculations\n",
-      "v1=(2*3.14*a*n1*math.sqrt(2*dl))/y1# normalised frequency at y=1.310\n",
-      "v2=(2*3.14*a*n2*math.sqrt(2*dl))/y2# normalised frequency at y=1.550\n",
-      "wo=a*(0.65+(1.619/math.pow(v1,1.5))+2.879/math.pow(v1,3))\n",
-      "wp=wo-a*(0.016+1.567/math.pow(v1,7))\n",
-      "wo1=a*(0.65+(1.619/math.pow(v2,1.5))+2.879/math.pow(v2,3))\n",
-      "wp1=wo-a*(0.016+1.567/math.pow(v2,7))\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.4f %s' %(\" The value of wo = \",wo*pow(10,6),\"um\"))\n",
-      "print ('%s %.4f %s' %(\"\\n The value of wp = \",wp*pow(10,6),\"um\"))\n",
-      "print ('%s %.4f %s' %(\"\\n The value of wo1 = \",wo1*pow(10,6),\"um\"))\n",
-      "print ('%s %.4f %s' %(\"\\n The value of wp1 = \",wp1*pow(10,6),\"um\"))\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The value of wo =  5.2031 um\n",
-        "\n",
-        " The value of wp =  5.1253 um\n",
-        "\n",
-        " The value of wo1 =  6.2264 um\n",
-        "\n",
-        " The value of wp1 =  5.0980 um\n"
-       ]
-      }
-     ],
-     "prompt_number": 94
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 31: PgNo-268"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Initialisation of variables\n",
-      "y=1.30*math.pow(10,-6) #  operating wavelength in m\n",
-      "dn1=math.pow(10,-6)\n",
-      "dn2=math.pow(10,-5)\n",
-      "\n",
-      "# Calculations\n",
-      "db1=(dn1*2*3.14)/y# in per m\n",
-      "db2=(dn2*2*3.14)/y# in per m\n",
-      "Lp1=(2*3.14)/(db1)# beat length in m\n",
-      "Lp2=(2*3.14)/(db2)# beat length in m\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The max core radius = \",db1,\"um\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The max core radius = \",db2,\"um\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The beat length = \",Lp1,\"m\"))\n",
-      "print ('%s %.1f %s' %(\"\\n The beat length = \",Lp2*100,\"cm\"))\n",
-      "print (\"\\n Hence, range of beat length; 13cm-1.3m\")"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The max core radius =  4.83 um\n",
-        "\n",
-        " The max core radius =  48.31 um\n",
-        "\n",
-        " The beat length =  1.30 m\n",
-        "\n",
-        " The beat length =  13.0 cm\n",
-        "\n",
-        " Hence, range of beat length; 13cm-1.3m\n"
-       ]
-      }
-     ],
-     "prompt_number": 95
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 32: PgNo-269"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable initialisation\n",
-      "n1=1.48     #  core refractive index\n",
-      "dl=0.0027\n",
-      "a=4.4*math.pow(10,-6) # radius in m\n",
-      "y=1.32*math.pow(10,-6) # operating wavelength in m\n",
-      "n2=n1*(1-dl)\n",
-      "c=3*math.pow(10,8) # the speed of ligth in m/s\n",
-      "v=(2*3.14*a*n1*math.sqrt(2*dl))/y\n",
-      "VD=0.080+0.549*math.pow((2.834-v),2)\n",
-      "DW=(-1)*(n2*dl*VD)/(c*y) # wavelength dispersion in s /um/m\n",
-      "Dw=DW*math.pow(10,6)  # wavelength dispersion in ps /nm/km\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.4f %s' %(\" The wavelength dispersion =  \",Dw,\"ps n/m/km\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The wavelength dispersion =   -2.5213 ps n/m/km\n"
-       ]
-      }
-     ],
-     "prompt_number": 96
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 33: PgNo-271"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "#Variable initialisation\n",
-      "n1=1.48 #  core refractive index\n",
-      "dl=0.01 #  refractive index difference\n",
-      "c=3*math.pow(10,8) # the speed of light in m/s\n",
-      "y=1.55 # wavelength in um\n",
-      "DM=7.0 # in ps/nm-km\n",
-      "DW=(-1)*DM # in ps/nm-km\n",
-      "\n",
-      "# calculations\n",
-      "X=math.pow(-10,12)*(n1*dl)/(c*y)# in ps/nm/km\n",
-      "Z=(DW/X)-0.08\n",
-      "V=2.834-math.sqrt(-Z/0.549)\n",
-      "a=(V*y)/(2*math.pi*n1*math.sqrt(2*dl))# core radius in um\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The core radius = \",a,\"um\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The core radius =  2.47 um\n"
-       ]
-      }
-     ],
-     "prompt_number": 97
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
-\ No newline at end of file
diff --git a/Optical_Fiber_Communication/Chapter6.ipynb b/Optical_Fiber_Communication/Chapter6.ipynb
deleted file mode 100755
index 9b5380f8..00000000
--- a/Optical_Fiber_Communication/Chapter6.ipynb
+++ /dev/null
@@ -1,104 +0,0 @@
-{
- "metadata": {
-  "name": "",
-  "signature": "sha256:ade43627b2f5d9f9e9fc6f1fe77b719e4d5ca9dd8c4d3cb361adefbae3d62e1a"
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 6: Optical Sources LEDs"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1: PgNo-277"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Initialisation of variables\n",
-      "r=125*math.pow(10,-6) # cladding radius in meter\n",
-      "R=8*math.pow(10,-2) # curve of radius in meter\n",
-      "s=((R+2*r)/(R+r))-1\n",
-      "s_p=s*100 # percentage of strain\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The percentage of strain = \",s_p,\"%\"))\n",
-      "print (\"\\n If this condition is maintained the fiber will maintain without any break \")\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The percentage of strain =  0.16 %\n",
-        "\n",
-        " If this condition is maintained the fiber will maintain without any break \n"
-       ]
-      }
-     ],
-     "prompt_number": 1
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2: PgNo-279"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# initialisation of variables\n",
-      "w=40*math.pow(10,-3) # cable weighing in kg/m\n",
-      "R=20*math.pow(10,-2) # radius of curvature in meter\n",
-      "n=0.19 # co-efficient of friction\n",
-      "x=(3.14/4) # angle in rad\n",
-      "\n",
-      "# calculations\n",
-      "si=42.36   # pulling tension at the entrance in kg\n",
-      "X=(si/(w*R))\n",
-      "Y=math.asinh(si/(w*R))\n",
-      "Z=w*R*math.sinh(n*x+Y) # puttling tension at the exit of an optical cable\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.3f %s' %(\" The puttling tension at the exit of an optical cable = \",Z,\"kg\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The puttling tension at the exit of an optical cable =  49.173 kg\n"
-       ]
-      }
-     ],
-     "prompt_number": 2
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
-\ No newline at end of file
diff --git a/Optical_Fiber_Communication/Chapter7.ipynb b/Optical_Fiber_Communication/Chapter7.ipynb
deleted file mode 100755
index b4eca185..00000000
--- a/Optical_Fiber_Communication/Chapter7.ipynb
+++ /dev/null
@@ -1,933 +0,0 @@
-{
- "metadata": {
-  "name": "",
-  "signature": "sha256:915bbc296599c9cae8476366ab28673955be075640a27c082930b79dfed61501"
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 7: Optical Detectors"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1: PgNo-284"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Initialisation of variables\n",
-      "n1=1.46    # core refractive index\n",
-      "n=1        # refractive index due to air\n",
-      "r=math.pow(((n1-n)/(n1+n)),2)\n",
-      "r1=0.03    # r take upto two decimal place\n",
-      "l_s=-10*math.log(1-r1)/math.log(10) # fiber loss in db\n",
-      "l_t=2*l_s  # total loss in db\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The fiber loss = \",l_s,\"db\"))\n",
-      "print (\"\\n there is a similar loss at the other interface \")\n",
-      "print ('%s %.2f %s' %(\"\\n The total fiber loss = \",l_t,\"db\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The fiber loss =  0.13 db\n",
-        "\n",
-        " there is a similar loss at the other interface \n",
-        "\n",
-        " The total fiber loss =  0.26 db\n"
-       ]
-      }
-     ],
-     "prompt_number": 7
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2: PgNo-285"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable declaration\n",
-      "n1=1.46 # core refractive index\n",
-      "n=1  # refractive index due to air\n",
-      "a=25*math.pow(10,-6) # core radius in m\n",
-      "y=3*math.pow(10,-6) # in m\n",
-      "\n",
-      "# calculations\n",
-      "A=(y/a)*math.pow((1-math.pow((y/(2*a)),2)),0.5)\n",
-      "B=math.acos(y/(2*a))\n",
-      "C=n1/n\n",
-      "M=(16*math.pow(C,2))/(math.pi*math.pow((1+C),4))\n",
-      "n_lat=M*(2*B-A) # coupling efficiency for multimode step index fiber\n",
-      "L_lat=-10*math.log(n_lat)/math.log(10) # insertion loss for lateral misalignment\n",
-      "n_lat1=(1/math.pi)*(2*B-A) # coupling efficiency when there is no air gap\n",
-      "L_lat1=-10*math.log(n_lat1)/math.log(10) # insertion loss for lateral misalignment when there is no air gap\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f ' %(\" The coupling efficiency for multimode step index fiber = \", n_lat))\n",
-      "print ('%s %.2f %s' %(\"\\n The insertion loss for lateral misalignment = \",L_lat,\"dB\"))\n",
-      "print ('%s %.2f ' %(\"\\n The coupling efficiency when there is no air gap = \", n_lat1))\n",
-      "print ('%s %.2f %s' %(\"\\n The insertion loss for lateral misalignment when there is no air gap = \",L_lat1,\"dB\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The coupling efficiency for multimode step index fiber =  0.86 \n",
-        "\n",
-        " The insertion loss for lateral misalignment =  0.65 dB\n",
-        "\n",
-        " The coupling efficiency when there is no air gap =  0.92 \n",
-        "\n",
-        " The insertion loss for lateral misalignment when there is no air gap =  0.34 dB\n"
-       ]
-      }
-     ],
-     "prompt_number": 8
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3: PgNo-287"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable declaration\n",
-      "n1=1.50     # core refractive index\n",
-      "n=1         # refractive index due to air\n",
-      "a=25*math.pow(10,-6) # core radius in m\n",
-      "y=4*math.pow(10,-6) # in m\n",
-      "\n",
-      "# calculations\n",
-      "A=(y/a)*math.pow((1-math.pow((y/(2*a)),2)),0.5)\n",
-      "B=math.acos(y/(2*a))\n",
-      "C=n1/n\n",
-      "M=(16*math.pow(C,2))/(math.pi*math.pow((1+C),4))\n",
-      "n_lat=M*(2*B-A)                # coupling efficiency for multimode step index fiber\n",
-      "L_lat=-10*math.log(n_lat)/math.log(10)   # insertion loss for lateral misalignment\n",
-      "dx=4*(math.pi/180)          # angular misalignment in radian\n",
-      "dl=0.02                #relative index difference\n",
-      "NA=n1*math.sqrt(2*dl)       # numerical aperture\n",
-      "n_ang=1-(0.069/(math.pi*NA)) # coupling efficiency due to angular misalignment\n",
-      "L_ang=-10*math.log(n_ang)/math.log(10) # loss due to angular misalignment\n",
-      "Lt=L_lat+L_ang         # total insertion loss in dB\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %( \" The total insertion loss = \",Lt,\"dB\"))\n",
-      "print (\"\\n the answer is wrong in the textbook \")"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The total insertion loss =  1.15 dB\n",
-        "\n",
-        " the answer is wrong in the textbook \n"
-       ]
-      }
-     ],
-     "prompt_number": 9
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 4: PgNo-292"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# variable initialisation\n",
-      "n1=1.46 # core refractive index\n",
-      "n=1 #refractive index due to air\n",
-      "a=1 # core radius in m\n",
-      "y=0.12  #lateral offset \n",
-      "\n",
-      "# Calculations\n",
-      "A=(y/a)*math.pow((1-math.pow((y/(2*a)),2)),0.5)\n",
-      "B=math.acos(y/(2*a))\n",
-      "C=n1/n\n",
-      "M=(16*math.pow(C,2))/(math.pi*math.pow((1+C),4))\n",
-      "n_lat=M*(2*B-A) #coupling efficiency when there is a smsll air gap\n",
-      "L_lat=-10*math.log(n_lat)/math.log(10) # insertion loss when there is a smsll air gap\n",
-      "n_lat1=(1/math.pi)*(2*B-A) # coupling efficiency when the joint is indexed matched\n",
-      "L_lat1=-10*math.log(n_lat1)/math.log(10) # insertion loss when the joint is indexed matched\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The insertion loss when there is a smsll air gap = \",L_lat,\"dB\"))\n",
-      "print ('%s %.2f %s' %( \"\\n The insertion loss when the joint is indexed matched = \",L_lat1,\"dB\"))\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The insertion loss when there is a smsll air gap =  0.65 dB\n",
-        "\n",
-        " The insertion loss when the joint is indexed matched =  0.34 dB\n"
-       ]
-      }
-     ],
-     "prompt_number": 10
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5: PgNo-296"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# variable initialisation\n",
-      "d1=60*math.pow(10,-6)# core diameter of fiber 1 in m\n",
-      "d2=50*math.pow(10,-6) # core diameter of fiber 1 in m\n",
-      "NA1=0.25 # numerical aerture of fiber 1\n",
-      "NA2=0.22 # numerical aerture of fiber 2\n",
-      "a1=2.0 # for fiber 1\n",
-      "a2=1.9 # for fiber 2\n",
-      "\n",
-      "# calculations\n",
-      "n_cd=math.pow((d2/d1),2)\n",
-      "n_NA=math.pow((NA2/NA1),2);\n",
-      "n_a=(1+(2/a1))/(1+(2/a2))\n",
-      "n_t=n_cd*n_NA*n_a # total coupling efficiency\n",
-      "Lt=-10*math.log(n_t)/math.log(10) #total loss at the joint in dB\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.3f ' %(\" The total coupling efficiency in the frw direction = \", n_t))\n",
-      "print ('%s %.2f %s' %(\"\\n The total loss at the joint in the frw direction = \",Lt,\"dB\"))\n",
-      "print (\"\\n In the backward direction n_cd & n_a are all unity therefore there will be no loss in the backward direction of transmission of the signal \")"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The total coupling efficiency in the frw direction =  0.524 \n",
-        "\n",
-        " The total loss at the joint in the frw direction =  2.81 dB\n",
-        "\n",
-        " In the backward direction n_cd & n_a are all unity therefore there will be no loss in the backward direction of transmission of the signal \n"
-       ]
-      }
-     ],
-     "prompt_number": 11
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 6: PgNo-298"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# variable initialisation\n",
-      "d1=80*math.pow(10,-6) #core diameter of fiber 1 in m\n",
-      "d2=60*math.pow(10,-6) #core diameter of fiber 1 in m\n",
-      "NA1=0.25    # numerical aerture of fiber 1\n",
-      "NA2=0.20   # numerical aerture of fiber 2\n",
-      "a1=1.9   # for fiber 1\n",
-      "a2=2.1  # for fiber 2\n",
-      "\n",
-      "# Calculations\n",
-      "n_cd=math.pow((d2/d1),2)\n",
-      "n_NA=math.pow((NA2/NA1),2)\n",
-      "n_a=(1+(2/a1))/(1+(2/a2))\n",
-      "n_t=n_cd*n_NA*n_a # total coupling efficiency in the frw direction\n",
-      "Lt=-10*math.log(n_t)/math.log(10) # total loss at the joint in the frw direction in dB\n",
-      "n_cd1=1\n",
-      "n_NA1=1\n",
-      "n_a1=(1+(2/a2))/(1+(2/a1))\n",
-      "n_t1=n_cd1*n_NA1*n_a1 # total coupling efficiency in the backward direction\n",
-      "Lt1=-10*math.log(n_t1)/math.log(10)# total loss at the joint in the backward direction in dB\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The total loss at the joint in the frw direction = \",Lt,\"dB\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The total loss at the joint in the backward direction = \",Lt1,\"dB\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The total loss at the joint in the frw direction =  4.22 dB\n",
-        "\n",
-        " The total loss at the joint in the backward direction =  0.22 dB\n"
-       ]
-      }
-     ],
-     "prompt_number": 12
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 7: PgNo-303"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# variable initialisation\n",
-      "n1=1.5 # core refractive index\n",
-      "n=1.47 # refractive index due to air\n",
-      "a=1 # core radius in m\n",
-      "y=0.12 # lateral offset\n",
-      "\n",
-      "# calculations\n",
-      "A=(y/a)*math.pow((1-math.pow((y/(2*a)),2)),0.5)\n",
-      "B=math.acos(y/(2*a))\n",
-      "C=n1/n\n",
-      "M=(16*math.pow(C,2))/(math.pi*math.pow((1+C),4))\n",
-      "n_lat=M*(2*B-A) #coupling efficiency of the splice\n",
-      "L_lat=-10*math.log(n_lat)/math.log(10) #insertion loss of the splice\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %( \" The insertion loss of the splice = \",L_lat,\"dB\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The insertion loss of the splice =  0.35 dB\n"
-       ]
-      }
-     ],
-     "prompt_number": 13
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 8: PgNo-305"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable initialisation\n",
-      "L_f=0.036\n",
-      "n_f=math.pow(10,(-0.036))\n",
-      "# here we get a quadratic equation in n1 and on solving we get\n",
-      "n1=(2.17+math.sqrt(math.pow((-2.17),2)-4*1*1))/2 # refractive index of the fiber core\n",
-      "# Results\n",
-      "print ('%s %.3f' %(\" The refractive index of the fiber core = \", n1))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The refractive index of the fiber core =  1.506\n"
-       ]
-      }
-     ],
-     "prompt_number": 14
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 9: PgNo-309"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# variable declaration\n",
-      "n1=1.46 #core refractive index\n",
-      "n=4   # refractive index due to air\n",
-      "x=math.pi/180\n",
-      "A=(16*math.pow(n1,2))/(math.pow((1+n1),4))\n",
-      "B=n*x\n",
-      "n_ang=math.pow(10,(-0.06)) # angular coupling efficiency\n",
-      "NA=B/((math.pi)*(1-(n_ang/A))) # numerical aperture\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f' %(\" The numerical aperture = \", NA))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The numerical aperture =  0.34\n"
-       ]
-      }
-     ],
-     "prompt_number": 15
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 10: PgNo-311"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable declaration\n",
-      "y=5*math.pow(10,-6)   # lateral misalignment in m\n",
-      "a=25*math.pow(10,-6)  # core diameter in m\n",
-      "Lt=0.85*(y/a)    # misalignment loss\n",
-      "n_c=1-Lt         # coupling efficiency\n",
-      "L_i=-10*math.log(n_c)/math.log(10) # insertion loss in dB\n",
-      "Lt1=0.75*(y/a)   # misalignment loss if we have both guided and leaky modes\n",
-      "n_c1=1-Lt1       # coupling efficiency\n",
-      "L_i1=-10*math.log(n_c1)/math.log(10) # insertion loss in dB if we have both guided and leaky modes\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The insertion loss = \",L_i,\"dB\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The insertion loss,if we have both guided and leaky modes = \",L_i1,\"dB\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The insertion loss =  0.81 dB\n",
-        "\n",
-        " The insertion loss,if we have both guided and leaky modes =  0.71 dB\n"
-       ]
-      }
-     ],
-     "prompt_number": 16
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11: PgNo-314"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable declaration\n",
-      "n1=1.5 # core refractive index\n",
-      "n=1  # refractive index due to air\n",
-      "x=5*math.pi/180\n",
-      "\n",
-      "# Calculations\n",
-      "C=n1/n\n",
-      "A=(16*math.pow(C,2))/(math.pow((1+C),4))\n",
-      "B=n*x\n",
-      "NA=0.22 # numerical aperture\n",
-      "n_ang=A*(1-(B/(math.pi*NA))) # angular coupling efficiency\n",
-      "L_ang=-10*math.log(n_ang)/math.log(10) # inserion loss when NA=0.22\n",
-      "NA1=0.32 # numerical aperture\n",
-      "n_ang1=A*(1-(B/(math.pi*NA1))) # angular coupling efficiency\n",
-      "L_ang1=-10*math.log(n_ang1)/math.log(10) # inserion loss when NA=0.32\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The inserion loss when NA=0.22 = \",L_ang,\"dB\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The inserion loss when NA=0.32 = \",L_ang1,\"dB\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The inserion loss when NA=0.22 =  0.94 dB\n",
-        "\n",
-        " The inserion loss when NA=0.32 =  0.75 dB\n"
-       ]
-      }
-     ],
-     "prompt_number": 17
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 12: PgNo-315"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable declaration\n",
-      "V=2.50 # normalised frequency\n",
-      "n1=1.5 # core refractive index\n",
-      "a=4.5*math.pow(10,-6) # core radius in m\n",
-      "NA=0.2 # numerical aperture\n",
-      "y=3*math.pow(10,-6) # lateral misalignment in m\n",
-      "w=a*((0.65+1.62*math.pow((V),-1.5)+2.88*math.pow((V),-6))/math.pow(2,0.5)) # normalised spot size in m\n",
-      "T1=2.17*math.pow((y/w),2) # Loss due to lateral offset in dB\n",
-      "x=(math.pi/180)*w\n",
-      "Ta=2.17*math.pow(((x*n1*V)/(a*NA)),2) # loss due to angular misalignment in dB\n",
-      "T=T1+Ta # total insertion loss in dB\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.3f %s' %(\" The total insertion loss  = \",T,\"dB\"))\n",
-      "print (\"\\n The answer is wrong in the textbook \")"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The total insertion loss  =  1.813 dB\n",
-        "\n",
-        " The answer is wrong in the textbook \n"
-       ]
-      }
-     ],
-     "prompt_number": 18
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 13: PgNo-317"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# variable declaration\n",
-      "P1=65       # optical power in uW\n",
-      "P2=0.005    #output power at port 2 in uW\n",
-      "P3=24       # output power at port 3 in uW\n",
-      "P4=26.5     #output power at port 4 in uW\n",
-      "\n",
-      "# Calculations\n",
-      "Le=10*math.log(P1/(P3+P4))/math.log(10) # Excess loss in dB\n",
-      "Le1=10*math.log(P1/P3)/math.log(10) # insertion loss port 1 to 3 in dB\n",
-      "Le2=10*math.log(P1/P4)/math.log(10) # insertion loss port 1 to 4 in dB\n",
-      "ct=10*math.log(P2/P1)/math.log(10) # cross talk in dB\n",
-      "sr=(P3/(P3+P4))*100 # split ratio\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The Excess loss = \",Le,\"dB\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The insertion loss port 1 to 3  = \",Le1,\"dB\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The insertion loss port 1 to 4  = \",Le2,\"dB\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The cross talk = \",ct,\"dB\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The split ratio = \",sr,\"%\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The Excess loss =  1.10 dB\n",
-        "\n",
-        " The insertion loss port 1 to 3  =  3.01 dB\n",
-        "\n",
-        " The insertion loss port 1 to 4  =  3.90 dB\n",
-        "\n",
-        " The cross talk =  -41.14 dB\n",
-        "\n",
-        " The split ratio =  47.52 %\n"
-       ]
-      }
-     ],
-     "prompt_number": 19
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14: PgNo-318"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# variable initialisation\n",
-      "n=1.0\n",
-      "n1=1.48\n",
-      "r=math.pow(((n1-n)/(n1+n)),2) # fresnel's reflection\n",
-      "Ls=-10*math.log(1-r)/math.log(10) #optical loss in dB\n",
-      "Lt=2*Ls # total fresnel loss\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The total fresnel loss = \",Lt,\"dB\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The total fresnel loss =  0.33 dB\n"
-       ]
-      }
-     ],
-     "prompt_number": 20
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 15: PgNo-322"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "#Variable declaration\n",
-      "NA1=0.32 # numerical aperture for fiber1\n",
-      "NA2=0.22 # numerical aperture for fiber2\n",
-      "Lc=20*math.log(NA1/NA2)/math.log(10) #NA mismatch coupling loss\n",
-      "\n",
-      "#Results\n",
-      "print ('%s %.2f %s' %(\" The NA mismatch coupling loss = \",Lc,\"dB\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The NA mismatch coupling loss =  3.25 dB\n"
-       ]
-      }
-     ],
-     "prompt_number": 21
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 16: PgNo-325"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# variable initialisation\n",
-      "P0=250.0 # optical power in uW\n",
-      "P1=80.0 # output power at port 1 in uW\n",
-      "P2=70.0 # output power at port 2 in uW\n",
-      "P3=5*math.pow(10,-3) # output power at port 3 in uW\n",
-      "\n",
-      "# calculations\n",
-      "cr=(P2/(P1+P2))*100 # coupling ratio\n",
-      "Le=10*math.log(P0/(P1+P2))/math.log(10) # Excess loss in dB\n",
-      "Le1=10*math.log(P0/P1)/math.log(10) # insertion loss port 0 to 1 in dB\n",
-      "Le2=10*math.log(P0/P2)/math.log(10) # insertion loss port 0 to 2 in dB\n",
-      "ct=10*math.log(P3/P0)/math.log(10)  #cross talk in dB\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The coupling ratio = \",cr,\"%\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The Excess loss = \",Le,\"dB\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The insertion loss port 0 to 1  = \",Le1,\"dB\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The insertion loss port 0 to 2 = \",Le2,\"dB\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The cross talk = \",ct,\"dB\"))\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The coupling ratio =  46.67 %\n",
-        "\n",
-        " The Excess loss =  2.22 dB\n",
-        "\n",
-        " The insertion loss port 0 to 1  =  4.95 dB\n",
-        "\n",
-        " The insertion loss port 0 to 2 =  5.53 dB\n",
-        "\n",
-        " The cross talk =  -46.99 dB\n"
-       ]
-      }
-     ],
-     "prompt_number": 22
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 17: PgNo-327"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable declaration\n",
-      "P_21=4.0/5.0 # ratio of the input available at port2\n",
-      "P_31=1.0/5.0 # ratio of the input available at port3 \n",
-      "Lt=-10*math.log(P_21)/math.log(10) # throughput loss\n",
-      "Lp=-10*math.log(P_31)/math.log(10) # tap loss\n",
-      "Le=-10*math.log(P_21+P_31)/math.log(10) # excess loss\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The throughput loss = \",Lt,\"dB\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The tap loss = \",Lp,\"dB\"))\n",
-      "print (\"\\n Directionality=-10*log(0/Pi=infinity)\")\n",
-      "print ('%s %.1f %s' %(\"\\n The excess loss = \",Le,\"dB\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The throughput loss =  0.97 dB\n",
-        "\n",
-        " The tap loss =  6.99 dB\n",
-        "\n",
-        " Directionality=-10*log(0/Pi=infinity)\n",
-        "\n",
-        " The excess loss =  -0.0 dB\n"
-       ]
-      }
-     ],
-     "prompt_number": 23
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 18: PgNo-329"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable declaration\n",
-      "Le=4 # excess loss in dB\n",
-      "D=60 # Directionality in dB\n",
-      "P_41=math.pow(10,-6) # the ratio of P4 to P1\n",
-      "P_31=0.670/5 # the ratio of P3 to P1\n",
-      "P_21=P_31*4 # the ratio of P2 to P1\n",
-      "Lt=-10*math.log(P_21)/math.log(10) # throughput loss\n",
-      "Lp=-10*math.log(P_31)/math.log(10) # tap loss\n",
-      "Ls=-10*math.log(0.670)/math.log(10) # loss due to radiation scattering in dB\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The fraction of the input power goes to each of the ports = \",P_21,\"dB\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The throughput loss = \",Lt,\"dB\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The tap loss = \",Lp,\"dB\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The loss due to radiation scattering = \",Ls,\"dB\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The fraction of the input power goes to each of the ports =  0.54 dB\n",
-        "\n",
-        " The throughput loss =  2.71 dB\n",
-        "\n",
-        " The tap loss =  8.73 dB\n",
-        "\n",
-        " The loss due to radiation scattering =  1.74 dB\n"
-       ]
-      }
-     ],
-     "prompt_number": 24
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 19: PgNo-330"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable declaration\n",
-      "L1=1.5 # length in km\n",
-      "L2=2/1000 # length in km\n",
-      "Pi=50.1*math.pow(10,-6) # optical power in W\n",
-      "Po=385.4*math.pow(10,-6) # output power in W\n",
-      "a=(10/(L1-L2))*math.log(Po/Pi)/math.log(10) # attenuation per km\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The attenuation per km = \",a,\"dB/km\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The attenuation per km =  5.91 dB/km\n"
-       ]
-      }
-     ],
-     "prompt_number": 25
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 20: PgNo-334"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable initialisation\n",
-      "Psc=5.31*math.pow(10,-9)\n",
-      "Popt=98.45*math.pow(10,-6) \n",
-      "L=5.99 # length in km\n",
-      "asc=(4.343*math.pow(10,5)/L)*(Psc/Popt) # scattering loss in the fiber in dB\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The scattering loss in the fiber = \",asc,\"dB/km\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The scattering loss in the fiber =  3.91 dB/km\n"
-       ]
-      }
-     ],
-     "prompt_number": 26
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
-\ No newline at end of file
diff --git a/Optical_Fiber_Communication/Chapter8.ipynb b/Optical_Fiber_Communication/Chapter8.ipynb
deleted file mode 100755
index 57a8dd8b..00000000
--- a/Optical_Fiber_Communication/Chapter8.ipynb
+++ /dev/null
@@ -1,1192 +0,0 @@
-{
- "metadata": {
-  "name": "",
-  "signature": "sha256:a1fc86a1745331cbb94487da02761804f9fca4fd4c628ee53c6bfd5a750d81a6"
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 8: Optical Fiber Communication System"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 1: PgNo-339"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable initialisation\n",
-      "tr=40.0     # rediative life time in ns\n",
-      "tnr=60.0    # nonrediative life time in ns\n",
-      "i=35*math.pow(10,-3) # drive current in amp\n",
-      "y=0.85*math.pow(10,-6)# wavelength in m\n",
-      "h=6.626*math.pow(10,-34)# plank constant\n",
-      "c=3*math.pow(10,8)# the speed of light in m/s\n",
-      "eq=1.602*math.pow(10,-19)# charge\n",
-      "\n",
-      "# calculations\n",
-      "t=tr*tnr/(tr+tnr)# total carrier recombination lifetime ns\n",
-      "ni=t/tr     # internal quantam efficiency\n",
-      "pil=(ni*h*c*i)/(eq*y)# internal power in watt\n",
-      "p_int=pil*math.pow(10,3)# internal power in mW\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.f %s' %(\" The total carrier recombination lifetime = \",t,\"ns\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The internal power = \",p_int,\"mW\"))\n",
-      "print (\"\\n The answer is wrong in textbook \")"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The total carrier recombination lifetime =  24 ns\n",
-        "\n",
-        " The internal power =  30.66 mW\n",
-        "\n",
-        " The answer is wrong in textbook \n"
-       ]
-      }
-     ],
-     "prompt_number": 33
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2: PgNo-341"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Initialisation of variables\n",
-      "tr=30.0 # rediative life time in ns\n",
-      "tnr=50.0  # nonrediative life time in ns\n",
-      "i=40*math.pow(10,-3)  # drive current in amp\n",
-      "pil=28.4*math.pow(10,-3) # internal power in watt\n",
-      "h=6.626*math.pow(10,-34) # plank constant\n",
-      "c=3*math.pow(10,8)  # the speed of light in m/s\n",
-      "eq=1.602*math.pow(10,-19) # charge\n",
-      "t=tr*tnr/(tr+tnr) # total carrier recombination lifetime ns\n",
-      "ni=t/tr    # internal quantam efficiency\n",
-      "y=(ni*h*c*i)/(eq*pil) # peak emission wavelength in m\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The total carrier recombination lifetime = \",t,\"ns\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The peak emission wavelength = \",y*pow(10,6),\"um\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The total carrier recombination lifetime =  18.75 ns\n",
-        "\n",
-        " The peak emission wavelength =  1.09 um\n"
-       ]
-      }
-     ],
-     "prompt_number": 34
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3: PgNo-345"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable initialisation\n",
-      "nx=3.6  # refractive index\n",
-      "Fn=0.68 # transmission factor\n",
-      "pe_pi=(Fn)/(4*math.pow(nx,2))\n",
-      "pi_p=0.3\n",
-      "nep=pe_pi*pi_p # external power efficiency\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\"The external power efficiency = \",nep*100,\"%\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "The external power efficiency =  0.39 %\n"
-       ]
-      }
-     ],
-     "prompt_number": 35
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 4: PgNo-347"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable initialisation\n",
-      "n=3.6 # core refractive index\n",
-      "NA=0.15 # numerical aperture\n",
-      "nc=math.pow(NA,2) # coupling efficiency\n",
-      "l_s=-10*math.log(nc)/math.log(10) # loss in db\n",
-      "pe_pi=0.023*0.0013  # from ex 8.3\n",
-      "pc=-10*math.log(pe_pi)/math.log(10) # loss in decibels relative to Pint\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The coupling efficiency = \",nc*100,\"%\"))\n",
-      "print ('%s %.3f %s' %(\"\\n The loss = \",l_s,\"db\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The loss in decibels relative to Pint= \",pc,\"db\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The coupling efficiency =  2.25 %\n",
-        "\n",
-        " The loss =  16.478 db\n",
-        "\n",
-        " The loss in decibels relative to Pint=  45.24 db\n"
-       ]
-      }
-     ],
-     "prompt_number": 36
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5: PgNo-348"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable initialisation\n",
-      "r=45*math.pow(10,-6) # radius in m\n",
-      "NA=0.3 # numerical aperture\n",
-      "rd=40 # radiance\n",
-      "A=3.14*math.pow((r*100),2) # area in cm^2\n",
-      "pe=3.14*(1-r)*A*rd*math.pow(NA,2) # optical power coupled into the fiber\n",
-      "Pe=pe*math.pow(10,4) # optical power coupled into the fiber uW\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.3f %s' %(\" The optical power coupled into the fiber = \",Pe,\"uW\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The optical power coupled into the fiber =  7.187 uW\n"
-       ]
-      }
-     ],
-     "prompt_number": 37
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 6: PgNo-351"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable initialisation\n",
-      "pc=150*math.pow(10,-6) # coupling power W\n",
-      "p=20*math.pow(10,-3)*2 # optical power W\n",
-      "npc=pc/p # overall efficiency\n",
-      "Npc=npc*100 # percentage of overall efficiency\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The percentage of overall efficiency = \",Npc,\"%\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The percentage of overall efficiency =  0.37 %\n"
-       ]
-      }
-     ],
-     "prompt_number": 38
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 7: PgNo-357"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable initialisation\n",
-      "n=1.5 # refractive index\n",
-      "L=0.05  #crystal length in m\n",
-      "y=0.5*math.pow(10,-6) #  wavelength in m\n",
-      "c=3*math.pow(10,8) # speed of light in m/s\n",
-      "q=2*n*L/y # the number of longitudinal modes\n",
-      "df=c/(2*n*L) # frequency separation of the modes in Hz\n",
-      "Df=df/math.pow(10,9) # frequency separation of the modes in GHz\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %d ' %(\" The number of longitudinal modes = \",q))\n",
-      "print ('%s %.2f %s' %(\"\\n The frequency separation of the modes = \",Df,\"GHz\"))\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The number of longitudinal modes =  300000 \n",
-        "\n",
-        " The frequency separation of the modes =  2.00 GHz\n"
-       ]
-      }
-     ],
-     "prompt_number": 39
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 8: PgNo-358"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable declaration\n",
-      "Eg=1.43 # bandgap energy in eV\n",
-      "dy=0.15*math.pow(10,-9);\n",
-      "c=3*math.pow(10,8) # speed of light in m/s\n",
-      "y=1.24/Eg  # in um\n",
-      "y1=y*math.pow(10,-6) # wavelength of optical emission in m\n",
-      "df=(c*dy)/math.pow(y1,2) # the line width in Hz\n",
-      "Df=df/math.pow(10,9) # the line width in GHz\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The wavelength of optical emission  = \",y,\"um\"))\n",
-      "print ('%s %.4f %s' %(\"\\n The frequency separation of the modes = \",Df,\"GHz\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The wavelength of optical emission  =  0.87 um\n",
-        "\n",
-        " The frequency separation of the modes =  59.8468 GHz\n"
-       ]
-      }
-     ],
-     "prompt_number": 40
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 9: PgNo-362"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable initialisation\n",
-      "n=3.6 # refractive index\n",
-      "c=3*math.pow(10,8)# speed of light in m/s\n",
-      "y=0.85*math.pow(10,-6)# wavelength in m\n",
-      "df=275*math.pow(10,9) # frequency separation of the modes in Hz\n",
-      "L=c/(2*n*df) # crystal length in m\n",
-      "L1=L*math.pow(10,6) # crystal length in um\n",
-      "q=2*n*L/y # the number of longitudinal modes\n",
-      "\n",
-      "# results\n",
-      "print ('%s %.2f %s' %(\" The crystal length = \",L1,\"um\"))\n",
-      "print ('%s %d' %(\"\\n The the number of longitudinal modes = \",int(q)))\n",
-      "print (\"\\n answer is wrong in textbook \")"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The crystal length =  151.52 um\n",
-        "\n",
-        " The the number of longitudinal modes =  1283\n",
-        "\n",
-        " answer is wrong in textbook \n"
-       ]
-      }
-     ],
-     "prompt_number": 41
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 10: PgNo-364"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Initialisation of variables\n",
-      "nt=0.20# total efficiency\n",
-      "Eg=1.43# bandgap energy in eV\n",
-      "V=2.2# applied voltage in volts\n",
-      "nep=(nt*Eg)/V# external power efficiency\n",
-      "Nep=nep*100#  percentage of external power efficiency\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The external power efficiency = \",Nep,\"%\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The external power efficiency =  13.00 %\n"
-       ]
-      }
-     ],
-     "prompt_number": 42
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11: PgNo-367"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Initialisation of variables\n",
-      "h=0.35*math.pow(10,-3)# irradiance W/cm^2\n",
-      "po=0.45*math.pow(10,-3)# power output in watt\n",
-      "d=1.5 # separation distance in cm\n",
-      "x=math.sqrt((4*po)/(3.14*math.pow(d,2)*h)) # divergence angle in radians\n",
-      "X=(x*180)/3.14 # divergence angle in degree\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.3f %s' %(\" The divergence angle = \",X,\"degree \"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The divergence angle =  48.909 degree \n"
-       ]
-      }
-     ],
-     "prompt_number": 43
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 12: PgNo-369"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Initialisation of variables\n",
-      "ni=0.09 # normal efficiency\n",
-      "d=2*2.54 # separation distance in cm\n",
-      "x=0.2 # divergence angle in radians\n",
-      "vf=2.0 # forward voltage in volts\n",
-      "i_f=65*math.pow(10,-3) # forward current in amp\n",
-      "pil=vf*i_f # input power in Watt\n",
-      "po=ni*pil # output power in Watt\n",
-      "H=4*po/(3.14*math.pow(d,2)*math.pow(x,2)) # irradiance in watt/cm^2\n",
-      "H1=H*1000 # irradiance in mwatt/cm^2\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The irradiance = \",H1,\"mwatt/cm^2 \"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The irradiance =  14.44 mwatt/cm^2 \n"
-       ]
-      }
-     ],
-     "prompt_number": 44
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 13: PgNo-372"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# variable declaration\n",
-      "tr=3.5 # relative life time in ms\n",
-      "tnr=50 # nonrelative life time in ms\n",
-      "ni=tnr/(tr+tnr) # internal quantam efficiency\n",
-      "\n",
-      "# results\n",
-      "print ('%s %.2f %s' %(\" The internal quantam efficiency = \",ni*100,\"%\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The internal quantam efficiency =  93.46 %\n"
-       ]
-      }
-     ],
-     "prompt_number": 45
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14: PgNo-375"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# initialisation of variables\n",
-      "ni=0.15 # internal quantam efficiency\n",
-      "vf=2.0  # forward voltage in volts\n",
-      "i_f=15*math.pow(10,-3) # forward current in amp\n",
-      "x=25    # acceptance angle in degree\n",
-      "pil=vf*i_f # input power in Watt\n",
-      "po=ni*pil # output power in Watt\n",
-      "NA=(math.sin(x*math.pi/180))\n",
-      "nc=math.pow(NA,2) # numerical aperture\n",
-      "pf=nc*po # optical power coupled into optical fiber in w\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The optical power coupled into optical fiber = \",pf*1000,\"mW\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The optical power coupled into optical fiber =  0.80 mW\n"
-       ]
-      }
-     ],
-     "prompt_number": 46
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 15: PgNo-378"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Initialisation of variables\n",
-      "tnr=10  # nonrediative life time in ns\n",
-      "n_inj=0.80 # injection efficiency\n",
-      "n_ex=0.60 # extraction efficiency\n",
-      "nt=0.025 # total efficiency\n",
-      "nr=nt/(n_inj*n_ex) # non rediative life time in ns\n",
-      "tr=((1/nr)-1)*tnr # rediative life time in ns\n",
-      "# Results\n",
-      "print ('%s %.1f %s' %(\" The rediative life time = \",tr,\"ns\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The rediative life time =  182.0 ns\n"
-       ]
-      }
-     ],
-     "prompt_number": 47
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 16: PgNo-381"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable initialisation\n",
-      "tr=30*math.pow(10,-9) # rise time in s\n",
-      "Bw=0.35/tr # bandwidth in Hz\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.3f %s' %(\" The bandwidth = \",Bw/math.pow(10,6),\"MHz\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The bandwidth =  11.667 MHz\n"
-       ]
-      }
-     ],
-     "prompt_number": 48
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 17: PgNo-384"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Initialisation of variables\n",
-      "y=630*math.pow(10,-9)# operating wavelength in m\n",
-      "w=25*math.pow(10,-6) # spot size in m\n",
-      "x=2*y/(math.pi*w) # divergence angle in radians\n",
-      "x1=x*180/math.pi #  divergence angle in degree\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.3f %s' %(\" The  divergence angle = \",x,\"radians\"))\n",
-      "print ('%s %.3f %s' %(\"\\n The  divergence angle = \",x1,\"degree\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The  divergence angle =  0.016 radians\n",
-        "\n",
-        " The  divergence angle =  0.919 degree\n"
-       ]
-      }
-     ],
-     "prompt_number": 49
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 18: PgNo-388"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable initialisation\n",
-      "y1=550*math.pow(10,-3)# peak of eyes response in um\n",
-      "y2=10.6 # standard wavelength in um\n",
-      "y3=2.39 # predominant IR line of He-Ne laser in um\n",
-      "E1=1.24/y1 # energy in electron volts\n",
-      "E2=1.24/y2 # energy in electron volts\n",
-      "E3=1.24/y3 # energy in electron volts\n",
-      "\n",
-      "# results\n",
-      "print ('%s %.3f %s' %(\" The  energy = \",E1,\"electron volts\"))\n",
-      "print ('%s %.3f %s' %(\"\\n The energy = \",E2,\"electron volts\"))\n",
-      "print ('%s %.3f %s' %(\"\\n The energy = \",E3,\"electron volts\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The  energy =  2.255 electron volts\n",
-        "\n",
-        " The energy =  0.117 electron volts\n",
-        "\n",
-        " The energy =  0.519 electron volts\n"
-       ]
-      }
-     ],
-     "prompt_number": 50
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 19: PgNo-391"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# variable initialisation\n",
-      "Eg=1.4 # energy in electron volts\n",
-      "y=1.24/Eg # cut off wavelength in um\n",
-      "y1=y*1000 # cut off wavelength in nm\n",
-      "# Results\n",
-      "print ('%s %.4f %s' %(\" The  cut off wavelength = \",y1,\"nm\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The  cut off wavelength =  885.7143 nm\n"
-       ]
-      }
-     ],
-     "prompt_number": 51
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 20: PgNo-394"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable initialisation\n",
-      "y=1200*math.pow(10,-9)# operating wavelength in m\n",
-      "w=5*math.pow(10,-6)# spot size in m\n",
-      "x=2*y/(math.pi*w)# divergence angle in radians\n",
-      "x1=x*180/math.pi #  divergence angle in degree\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.3f %s' %(\" The  divergence angle = \",x,\"radians\"))\n",
-      "print ('%s %.3f %s' %(\"\\n The  divergence angle = \",x1,\"degree\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The  divergence angle =  0.153 radians\n",
-        "\n",
-        " The  divergence angle =  8.754 degree\n"
-       ]
-      }
-     ],
-     "prompt_number": 52
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 21: PgNo-395"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Initialisation of variables\n",
-      "n1=1.48 # core refractive index\n",
-      "n2=1.46 # cladding refractive index \n",
-      "NA=math.sqrt(math.pow(n1,2)-math.pow(n2,2)) # numerical aperture\n",
-      "xa=(math.asin(NA))*(180/math.pi) # acceptance angle in degree\n",
-      "nc=math.pow(NA,2) # coupling efficiency\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The  acceptance angle = \",xa,\"degree\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The coupling efficiency = \",nc*100,\"%\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The  acceptance angle =  14.03 degree\n",
-        "\n",
-        " The coupling efficiency =  5.88 %\n"
-       ]
-      }
-     ],
-     "prompt_number": 53
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 22: PgNo-398"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Initialisation of variables\n",
-      "c=3*math.pow(10,8)  # speed of light in m/s\n",
-      "n=3.66 # for GaAs\n",
-      "L=150*math.pow(10,-6) # cavity length in m\n",
-      "dv=c/(2*n*L) #frequency separation in Hz\n",
-      "dv1=dv/math.pow(10,12) # frequency separation in GHz\n",
-      "h=6.64*math.pow(10,-34) # plank constant\n",
-      "q=1.6*math.pow(10,-19) # charge of an electron\n",
-      "dE=(h*dv)/q # energy separation eV\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.4f %s' %(\" The frequency separation = \",dv1,\"GHz\"))\n",
-      "print ('%s %.3f %s' %(\"\\n The energy separation = \",dE*1000,\"meV\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The frequency separation =  0.2732 GHz\n",
-        "\n",
-        " The energy separation =  1.134 meV\n"
-       ]
-      }
-     ],
-     "prompt_number": 54
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 23: PgNo-400"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# variable initialisation\n",
-      "po=2*math.pow(10,-3)# optical power in watts\n",
-      "I=100*math.pow(10,-3)# current in amp\n",
-      "V=2 # applied voltage in volt\n",
-      "pe=I*V # electrical power in watts\n",
-      "n=(po/pe)*100 # conversion efficiency\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The conversion efficiency = \",n,\"%\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The conversion efficiency =  1.00 %\n"
-       ]
-      }
-     ],
-     "prompt_number": 55
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 24: PgNo-403"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# variable initialisation\n",
-      "c=3*math.pow(10,8)  # speed of light in m/s\n",
-      "h=6.64*math.pow(10,-34) # plank constant\n",
-      "Eg=1.43 # gap energy in eV\n",
-      "y=(1.24*math.pow(10,-6))/Eg # wavelength in m\n",
-      "dy=0.1*math.pow(10,-9) # in m\n",
-      "df=(dy*c)/math.pow(y,2) # width in Hz\n",
-      "# Results\n",
-      "print ('%s %.3f %s' %(\" The wavelength = \",y*pow(10,6),\"um\"))\n",
-      "print ('%s %.4f %s' %(\"\\n The width = \",df/pow(10,9),\"GHz\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The wavelength =  0.867 um\n",
-        "\n",
-        " The width =  39.8979 GHz\n"
-       ]
-      }
-     ],
-     "prompt_number": 56
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 25: PgNo-407"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable declaration\n",
-      "tr=25.0 # rediative life time in ns\n",
-      "tnr=90.0 # nonrediative life time in ns\n",
-      "i=3.5*math.pow(10,-3) # drive current in amp\n",
-      "y=1.31*math.pow(10,-6) # wavelength in m\n",
-      "h=6.625*math.pow(10,-34) # plank constant\n",
-      "c=3*math.pow(10,8) # the speed of light in m/s\n",
-      "eq=1.6*math.pow(10,-19 )# charge\n",
-      "t=tr*tnr/(tr+tnr) # total carrier recombination lifetime ns\n",
-      "ni=t/tr # internal quantam efficiency\n",
-      "pil=(ni*h*c*i)/(eq*y) # internal power in watt\n",
-      "p_int=pil*pow(10,3) # internal power in mW\n",
-      "P=p_int/(ni*(ni+1)) # power emitted in mW\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The total carrier recombination lifetime = \",t,\"ns\"))\n",
-      "print ('%s %.2f ' %(\"\\n The internal quantam efficiency = \", ni))\n",
-      "print ('%s %.2f %s' %(\"\\n The internal power = \",p_int,\"mW\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The power emitted = \",P,\"mW\"))\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The total carrier recombination lifetime =  19.57 ns\n",
-        "\n",
-        " The internal quantam efficiency =  0.78 \n",
-        "\n",
-        " The internal power =  2.60 mW\n",
-        "\n",
-        " The power emitted =  1.86 mW\n"
-       ]
-      }
-     ],
-     "prompt_number": 57
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 26: PgNo-409"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable initialisation\n",
-      "nt=0.18 # total efficiency\n",
-      "Eg=1.43 # band gape energy eV\n",
-      "V=2.5 # appied voltage in volt\n",
-      "n_ex=(nt*(Eg/V))*100 # external efficiency\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The external efficiency = \",n_ex,\"%\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The external efficiency =  10.30 %\n"
-       ]
-      }
-     ],
-     "prompt_number": 58
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 27: PgNo-411"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Initialisation of variables\n",
-      "c=3*math.pow(10,8)   # speed of light in m/s\n",
-      "n=3.6      # for GaAs\n",
-      "df=278*math.pow(10,9)  # separation in Hz\n",
-      "y=0.87*math.pow(10,-6) # wavelength in m\n",
-      "L=c/(2*n*df) # cavity length in m\n",
-      "l=L*math.pow(10,6) # cavity length in um\n",
-      "L1=math.floor(l)*math.pow(10,-6) # cavity length in m\n",
-      "q=(2*n*L1)/y  # number of longitudinal modes\n",
-      "# Results\n",
-      "print ('%s %.3f %s' %(\" The cavity length = \",l,\"um\"))\n",
-      "print ('%s %d' %( \"\\n The number of longitudinal modes = \",int(q)))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The cavity length =  149.880 um\n",
-        "\n",
-        " The number of longitudinal modes =  1233\n"
-       ]
-      }
-     ],
-     "prompt_number": 59
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 28: PgNo-415"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Initialisation of variables\n",
-      "ac=14 # acceptance angle in degree\n",
-      "nc=math.pow((math.sin(ac*math.pi/180)),2) # coupling efficiency\n",
-      "l_s=-10*math.log(nc)/math.log(10) # loss in decibels\n",
-      "\n",
-      "# results\n",
-      "print ('%s %.3f ' %(\" The coupling efficiency = \",nc))\n",
-      "print ('%s %.3f %s' %(\"\\n The loss = \",l_s,\"decibels\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The coupling efficiency =  0.059 \n",
-        "\n",
-        " The loss =  12.326 decibels\n"
-       ]
-      }
-     ],
-     "prompt_number": 60
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 29: PgNo-417"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable initialisation\n",
-      "c=3*math.pow(10,8)# speed of light in m/s\n",
-      "n=3.7 # for GaAs\n",
-      "L=500*math.pow(10,-6) # cavity length in m\n",
-      "y=850*math.pow(10,-9)\n",
-      "df=c/(2*n*L) #frequency separation in Hz\n",
-      "df1=df/math.pow(10,9)  # frequency separation in GHz\n",
-      "dy=(y*y)/(2*L*n) # wavelength in m\n",
-      "dy1=dy*math.pow(10,9) # wavelength in nm\n",
-      "\n",
-      "# Resultsh\n",
-      "print ('%s %.4f %s' %(\" The frequency separation = \",df1,\"GHz\"))\n",
-      "print ('%s %.3f %s' %(\"\\n The wavelength separation = \",dy1,\"nm\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The frequency separation =  81.0811 GHz\n",
-        "\n",
-        " The wavelength separation =  0.195 nm\n"
-       ]
-      }
-     ],
-     "prompt_number": 61
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
-\ No newline at end of file
diff --git a/Optical_Fiber_Communication/Chapter9.ipynb b/Optical_Fiber_Communication/Chapter9.ipynb
deleted file mode 100755
index 367cadc1..00000000
--- a/Optical_Fiber_Communication/Chapter9.ipynb
+++ /dev/null
@@ -1,1146 +0,0 @@
-{
- "metadata": {
-  "name": "",
-  "signature": "sha256:e11123ba8b6bbada16d8c62d198839756136e69c9f0cc93a98384db776536508"
- },
- "nbformat": 3,
- "nbformat_minor": 0,
- "worksheets": [
-  {
-   "cells": [
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Chapter 9 : Optical Fiber System-I"
-     ]
-    },
-    {
-     "cell_type": "heading",
-     "level": 1,
-     "metadata": {},
-     "source": [
-      "Example 1: PgNo-424"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Initialisation of variables\n",
-      "e_c=550.0 # number of electron collected\n",
-      "p=800.0 # number of photon incident\n",
-      "n=e_c/p # quantum efficiency\n",
-      "eq=1.602*math.pow(10,-19)# charge\n",
-      "h=6.626*math.pow(10,-34)# plank constant\n",
-      "c=3*math.pow(10,8)# speed of light in m/s\n",
-      "y=1.3*math.pow(10,-6) #wavelength in m\n",
-      "R=(n*eq*y)/(h*c)# responsivity in A/W\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The responsivity = \",R,\"Amp/Watt\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The responsivity =  0.72 Amp/Watt\n"
-       ]
-      }
-     ],
-     "prompt_number": 31
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 2: PgNo-427"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable initialisation\n",
-      "eq=1.602*math.pow(10,-19)# charge\n",
-      "h=6.626*math.pow(10,-34)# plank constant\n",
-      "c=3*math.pow(10,8)# speed of light in m/s\n",
-      "y=0.85*math.pow(10,-6) # wavelength in m\n",
-      "R=0.274 # responsivity in A/W\n",
-      "n=(R*h*c)/(eq*y) # quantum efficiency\n",
-      "n1=n*100 # % of quantum efficiency\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The quantum efficiency = \",n1,\"%\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The quantum efficiency =  40.00 %\n"
-       ]
-      }
-     ],
-     "prompt_number": 32
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 3: PgNo-429"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable declaration\n",
-      "e_c=1.0  # number of electron collected\n",
-      "p=3.0    # number of photon incident\n",
-      "n=e_c/p # quantum efficiency\n",
-      "eq=1.602*math.pow(10,-19) # charge\n",
-      "h=6.626*math.pow(10,-34) # plank constant\n",
-      "c=3*math.pow(10,8) # speed of light in m/s\n",
-      "y=0.8*math.pow(10,-6) # wavelength in m\n",
-      "Eg=(h*c)/y # band gap energy in J\n",
-      "R=(n*eq*y)/(h*c)# responsivity in A/W\n",
-      "Po=math.pow(10,-7) # in W\n",
-      "Ip=R*Po # output photo current\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The quantum efficiency = \",n*100,\"%\"))\n",
-      "print ('%s %.2f %s' %(\"\\n band gap energy = \",Eg*pow(10,20),\"*10^-20 J\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The output photo current = \",Ip*pow(10,9),\"nA\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The quantum efficiency =  33.33 %\n",
-        "\n",
-        " band gap energy =  24.85 *10^-20 J\n",
-        "\n",
-        " The output photo current =  21.49 nA\n"
-       ]
-      }
-     ],
-     "prompt_number": 33
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 4: PgNo-432"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable initialisation\n",
-      "n=0.50 # quantum efficiency\n",
-      "eq=1.602*math.pow(10,-19)# charge\n",
-      "h=6.626*math.pow(10,-34)# plank constant\n",
-      "c=3*math.pow(10,8)# speed of light in m/s\n",
-      "y=0.85*math.pow(10,-6) # wavelength in m\n",
-      "R=(n*eq*y)/(h*c)# responsivity in A/W\n",
-      "Ip=math.pow(10,-6)# mean photo current\n",
-      "Po=Ip/R  # received optical power in W\n",
-      "f=c/y\n",
-      "re=(n*Po)/(h*f)\n",
-      "rp=re/n # number of received photons\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The responsivity = \",R,\"A/W\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The received optical power = \",Po*pow(10,6),\"uW\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The number of received photons = \",rp/pow(10,13),\"*10^13 photons/sec\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The responsivity =  0.34 A/W\n",
-        "\n",
-        " The received optical power =  2.92 uW\n",
-        "\n",
-        " The number of received photons =  1.25 *10^13 photons/sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 34
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 5: PgNo-435"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable initialisation\n",
-      "h=6.626*math.pow(10,-34)# plank constant\n",
-      "c=3*math.pow(10,8)   # speed of light in m/s\n",
-      "Eg=1.43         # in eV\n",
-      "Eg1=Eg*1.602*math.pow(10,-19) # in J\n",
-      "y=(h*c)/Eg1    # cut off wavelength in m\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The cut off wavelength = \",y*pow(10,6),\"um\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The cut off wavelength =  0.87 um\n"
-       ]
-      }
-     ],
-     "prompt_number": 35
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 6: PgNo-437"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Initialisation of variables\n",
-      "vd=2.5*math.pow(10,4)# carrier velocity in m/s\n",
-      "w=30*math.pow(10,-6)# width in m\n",
-      "Bm=vd/(2*math.pi*w)\n",
-      "Tm=1/Bm # max response time in sec\n",
-      "Tm1=Tm*math.pow(10,9) # max response time in ns\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The max response time = \",Tm1,\"ns\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The max response time =  7.54 ns\n"
-       ]
-      }
-     ],
-     "prompt_number": 36
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 7: PgNo-440"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable initialisation\n",
-      "n=0.65  # quantum efficiency\n",
-      "eq=1.602*math.pow(10,-19) # charge\n",
-      "h=6.626*math.pow(10,-34) # plank constant\n",
-      "c=3*math.pow(10,8) # speed of light in m/s\n",
-      "y=0.85*math.pow(10,-6)# wavelength in m\n",
-      "R=(n*eq*y)/(h*c)# responsivity in A/W\n",
-      "Po=0.35*math.pow(10,-6) # in W\n",
-      "Ip=R*Po # output photo current\n",
-      "I=9*math.pow(10,-6) # output current in A\n",
-      "M=I/Ip # multiplication factor\n",
-      "M1=math.ceil(M)\n",
-      "# Results\n",
-      "print \" The multiplication factor = \",int(M1)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The multiplication factor =  58\n"
-       ]
-      }
-     ],
-     "prompt_number": 37
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 8: PgNo-442"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable declaration\n",
-      "n=0.50  # quantum efficiency\n",
-      "eq=1.602*math.pow(10,-19) # charge\n",
-      "h=6.626*math.pow(10,-34) # plank constant\n",
-      "c=3*math.pow(10,8) # speed of light in m/s\n",
-      "Eg=1.5*math.pow(10,-19) # in J\n",
-      "y=(h*c)/Eg # cut off wavelength in m\n",
-      "f=c/y\n",
-      "R=(n*eq)/(h*f) # responsivity in A/W\n",
-      "Ip=2.7*math.pow(10,-6) # photo current in A\n",
-      "Po=Ip/R # incident optical power in W\n",
-      "Po1=Po*math.pow(10,6) # incident optical power in uW\n",
-      "\n",
-      "# results\n",
-      "print ('%s %.2f %s' %( \" The cut off wavelength = \",y*pow(10,6),\"um\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The responsivity = \",R,\"A/W \"))\n",
-      "print ('%s %.2f %s' %(\"\\n The incident optical power = \",Po1,\"uW\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The cut off wavelength =  1.33 um\n",
-        "\n",
-        " The responsivity =  0.53 A/W \n",
-        "\n",
-        " The incident optical power =  5.06 uW\n"
-       ]
-      }
-     ],
-     "prompt_number": 38
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 9: PgNo-445"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "#Variable declaration\n",
-      "n=0.15 # quantum efficiency\n",
-      "eq=1.6*math.pow(10,-19) # charge\n",
-      "h=6.63*math.pow(10,-34)# plank constant\n",
-      "c=3*math.pow(10,8) # speed of light in m/s\n",
-      "y=0.85*math.pow(10,-6) # cut off wavelength in m\n",
-      "f=c/y # frequency in Hz\n",
-      "R=(n*eq)/(h*f) # responsivity in A/W\n",
-      "# Results\n",
-      "print ('%s %.3f %s' %(\" The responsivity = \",R,\"A/W\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The responsivity =  0.103 A/W\n"
-       ]
-      }
-     ],
-     "prompt_number": 39
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 10: PgNo-448"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable initialisation\n",
-      "Iph=75*math.pow(10,-6) # output photocurrent in A\n",
-      "y=0.85 # operating wavelength in um\n",
-      "Pie=750*math.pow(10,-6) # incident optical power in uW\n",
-      "R=Iph/Pie # responsivity in A/W\n",
-      "n=1.24*R/y # external quantum efficiency\n",
-      "n1=n*100  # percentage of external quantum efficiency\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The responsivity = \",R,\"A/W\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The external quantum efficiency = \",n1,\"%\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The responsivity =  0.10 A/W\n",
-        "\n",
-        " The external quantum efficiency =  14.59 %\n"
-       ]
-      }
-     ],
-     "prompt_number": 40
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 11: PgNo-451"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable initialisation\n",
-      "Vs=math.pow(10,5) # saturation in m/s\n",
-      "W=7*math.pow(10,-6) # depletion layer width in m\n",
-      "tr=W/Vs # transit time in sec\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.1f %s' %(\" The transit time = \",tr*pow(10,12),\"ps\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The transit time =  70.0 ps\n"
-       ]
-      }
-     ],
-     "prompt_number": 41
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 12: PgNo-454"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable initialisation\n",
-      "Vs=3*math.pow(10,4)# saturation in m/s\n",
-      "W=25*math.pow(10,-6) # depletion layer width in m\n",
-      "tr=W/Vs # transit time in sec\n",
-      "f=0.35/tr # max 3 dB bandwidth Hz\n",
-      "f1=f/math.pow(10,6) # max 3 dB bandwidth Hz\n",
-      "\n",
-      "# results\n",
-      "print ('%s %.f %s' %(\" The max 3 dB bandwidth = \",f1,\"MHz\"))\n",
-      "print (\"\\n The answer is wrong in the textbook \")"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The max 3 dB bandwidth =  420 MHz\n",
-        "\n",
-        " The answer is wrong in the textbook \n"
-       ]
-      }
-     ],
-     "prompt_number": 42
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 13: PgNo-456"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# variable initialisation\n",
-      "Vs=3*math.pow(10,4) # saturation in m/s\n",
-      "W=25*math.pow(10,-6) # depletion layer width in m\n",
-      "E=10.5*math.pow(10,-11) # in F/m\n",
-      "RL=15*math.pow(10,6) # load resister in ohm\n",
-      "A=0.25*math.pow(10,-6) # area in m^2\n",
-      "tr=W/Vs # transit time in sec\n",
-      "Cj=E*A/W # junction capacitance in F\n",
-      "t=RL*Cj # time constant in sec\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.3f %s' %(\" The transit time = \",tr*pow(10,9),\"ns\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The junction capacitance = \",Cj*pow(10,12),\"pF\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The time constant = \",t*pow(10,6),\"us\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The transit time =  0.833 ns\n",
-        "\n",
-        " The junction capacitance =  1.05 pF\n",
-        "\n",
-        " The time constant =  15.75 us\n"
-       ]
-      }
-     ],
-     "prompt_number": 43
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 14: PgNo-459"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Initialisation of variables\n",
-      "Eg1=1.12    # band gap for Si in eV\n",
-      "Eg2=0.667   # band gap for Ge in eV\n",
-      "y_si=1.24/Eg1 # cut off wavelength for Si in um\n",
-      "y_he=1.24/Eg2 # cut off wavelength for Ge in um\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.3f %s' %(\" The cut off wavelength for Si  = \",y_si,\"um\"))\n",
-      "print ('%s %.3f %s' %(\"\\n The cut off wavelength for Ge = \",y_he,\"um\"))\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The cut off wavelength for Si  =  1.107 um\n",
-        "\n",
-        " The cut off wavelength for Ge =  1.859 um\n"
-       ]
-      }
-     ],
-     "prompt_number": 44
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 15: PgNo-463"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# variable declaration\n",
-      "n=0.50  # quantum efficiency\n",
-      "eq=1.6*math.pow(10,-19)# charge\n",
-      "h=6.626*math.pow(10,-34) # plank constant\n",
-      "c=3*math.pow(10,8) # speed of light in m/s\n",
-      "y=0.9*math.pow(10,-6) # wavelength in m\n",
-      "R=(n*eq*y)/(h*c) # responsivity in A/W\n",
-      "Ip=math.pow(10,-6) # mean photo current\n",
-      "Po=Ip/R # received optical power in W\n",
-      "f=c/y\n",
-      "re=(n*Po)/(h*f)\n",
-      "rp=re/n # number of received photons\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The responsivity = \",R,\"A/W\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The received optical power = \",Po*pow(10,6),\"uW\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The number of received photons = \",rp/pow(10,13),\"*10^13 photons/sec\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The responsivity =  0.36 A/W\n",
-        "\n",
-        " The received optical power =  2.76 uW\n",
-        "\n",
-        " The number of received photons =  1.25 *10^13 photons/sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 45
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 16: PgNo-466"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Initialisation of variables\n",
-      "R=0.40 # Responsivity in A/W\n",
-      "m=100*math.pow(10,-6) # incident flux in W/m-m\n",
-      "A=2  # area in m-m\n",
-      "Po=m*A # incident power in W\n",
-      "Ip=R*Po # photon current in A\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.f %s' %(\" The photon current = \",Ip*math.pow(10,6),\"uA\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The photon current =  80 uA\n"
-       ]
-      }
-     ],
-     "prompt_number": 46
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 17: PgNo-470"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable declaration\n",
-      "n=0.65      # quantum efficiency\n",
-      "eq=1.602*math.pow(10,-19) # charge\n",
-      "h=6.626*math.pow(10,-34) # plank constant\n",
-      "c=3*math.pow(10,8)  # speed of light in m/s\n",
-      "Eg=1.5*math.pow(10,-19) # in J\n",
-      "y=(h*c)/Eg   # cut off wavelength in m\n",
-      "f=c/y\n",
-      "R=(n*eq)/(h*f)  # responsivity in A/W\n",
-      "Ip=2.5*math.pow(10,-6) # photo current in A\n",
-      "Po=Ip/R    # incident optical power in W\n",
-      "Po1=Po*math.pow(10,6) # incident optical power in uW\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The cut off wavelength = \",y*math.pow(10,6),\"um\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The responsivity = \",R,\"A/W\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The incident optical power = \",Po1,\"uW\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The cut off wavelength =  1.33 um\n",
-        "\n",
-        " The responsivity =  0.69 A/W\n",
-        "\n",
-        " The incident optical power =  3.60 uW\n"
-       ]
-      }
-     ],
-     "prompt_number": 47
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 18: PgNo-472"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable declaration\n",
-      "h=6.626*math.pow(10,-34) # plank constant\n",
-      "c=3*math.pow(10,8) # speed of light in m/s\n",
-      "Eg=1.43 # in eV\n",
-      "Eg1=Eg*1.602*math.pow(10,-19) # in J\n",
-      "y=(h*c)/Eg1 # cut off wavelength in m\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.3f %s' %(\" The cut off wavelength = \",y*math.pow(10,6),\"um\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The cut off wavelength =  0.868 um\n"
-       ]
-      }
-     ],
-     "prompt_number": 48
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 19: PgNo-474"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable declaration\n",
-      "n=0.45  # quantum efficiency\n",
-      "h=6.62*math.pow(10,-34) # plank constant\n",
-      "c=3*math.pow(10,8) # speed of light in m/s\n",
-      "y=1.2*math.pow(10,-6) # cut off wavelength in m\n",
-      "Ic=20*math.pow(10,-6) # collector current in A\n",
-      "Po=120*math.pow(10,-6)# incident optical power in W\n",
-      "eq=1.602*math.pow(10,-19)# charge\n",
-      "Go=(h*c*Ic)/(y*Po*eq) # optical gain\n",
-      "h_e=Go/n # common emitter gain\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.3f ' %(\" The optical gain = \",Go))\n",
-      "print ('%s %.3f ' %(\"\\n The common emitter gain = \",h_e))\n"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The optical gain =  0.172 \n",
-        "\n",
-        " The common emitter gain =  0.383 \n"
-       ]
-      }
-     ],
-     "prompt_number": 49
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 20: PgNo-477"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Initialisation of variables\n",
-      "n=0.5   # quantum efficiency\n",
-      "eq=1.602*math.pow(10,-19) # charge\n",
-      "h=6.626*math.pow(10,-34) # plank constant\n",
-      "c=3*math.pow(10,8) # speed of light in m/s\n",
-      "y=1.3*math.pow(10,-6) # wavelength in m\n",
-      "R=(n*eq*y)/(h*c)# responsivity in A/W\n",
-      "Po=0.4*math.pow(10,-6) # in W\n",
-      "Ip=R*Po # output photo current\n",
-      "I=8*math.pow(10,-6) # output current in A\n",
-      "M=I/Ip # multiplication factor\n",
-      "\n",
-      "# Results\n",
-      "print \" The multiplication factor = \",int(M)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The multiplication factor =  38\n"
-       ]
-      }
-     ],
-     "prompt_number": 50
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 21: PgNo-481"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Initialisation of variables\n",
-      "n=0.85  # quantum efficiency\n",
-      "eq=1.6*math.pow(10,-19) # charge\n",
-      "h=6.625*math.pow(10,-34) # plank constant\n",
-      "c=3*math.pow(10,8) # speed of light in m/s\n",
-      "y=0.9*math.pow(10,-6) # wavelength in m\n",
-      "R=(n*eq*y)/(h*c)# responsivity in A/W\n",
-      "Po=0.6*math.pow(10,-6) # in W\n",
-      "Ip=R*Po # output photo current\n",
-      "I=10*math.pow(10,-6) # output current in A\n",
-      "M=I/Ip # multiplication factor\n",
-      "\n",
-      "# Results\n",
-      "print \" The multiplication factor = \",int(M)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The multiplication factor =  27\n"
-       ]
-      }
-     ],
-     "prompt_number": 51
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 22: PgNo-483"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable initialisation\n",
-      "e_c=1.2*math.pow(10,11) # number of electron collected\n",
-      "p=2*math.pow(10,11) # number of photon incident\n",
-      "n=e_c/p  # quantum efficiency\n",
-      "eq=1.602*math.pow(10,-19) # charge\n",
-      "h=6.626*math.pow(10,-34) # plank constant\n",
-      "c=3*math.pow(10,8)    # speed of light in m/s\n",
-      "E=1.5*math.pow(10,-19) # energy in J\n",
-      "\n",
-      "# Calculations\n",
-      "y=(h*c)/E  # wavelength in m\n",
-      "R=(n*eq*y)/(h*c)  # responsivity in A/W\n",
-      "Ip=2.6*math.pow(10,-6) # photocurrent in A\n",
-      "Po=Ip/R     # incident optical power in W\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The quantum efficiency = \",n*100,\"%\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The wavelength = \",y*pow(10,6),\"um\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The responsivity = \",R,\"Amp/Watt\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The incident optical power = \",Po*math.pow(10,6),\"uW\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The quantum efficiency =  60.00 %\n",
-        "\n",
-        " The wavelength =  1.33 um\n",
-        "\n",
-        " The responsivity =  0.64 Amp/Watt\n",
-        "\n",
-        " The incident optical power =  4.06 uW\n"
-       ]
-      }
-     ],
-     "prompt_number": 52
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 23: PgNo-485"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable initialisation\n",
-      "n=0.40  # quantum efficiency\n",
-      "eq=1.602*math.pow(10,-19) # charge\n",
-      "h=6.626*math.pow(10,-34) # plank constant\n",
-      "c=3*math.pow(10,8) # speed of light in m/s\n",
-      "y=1.35*math.pow(10,-6) # wavelength in m\n",
-      "R=(n*eq*y)/(h*c) # responsivity in A/W\n",
-      "Po=0.2*math.pow(10,-6) # in W\n",
-      "Ip=R*Po     # output photo current\n",
-      "I=4.9*math.pow(10,-6) # output current in A\n",
-      "M=I/Ip    # multiplication factor\n",
-      "\n",
-      "# Results\n",
-      "print \" The multiplication factor = \",int(M)"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The multiplication factor =  56\n"
-       ]
-      }
-     ],
-     "prompt_number": 53
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 24: PgNo-489"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable initialisation\n",
-      "n=0.55      # quantum efficiency\n",
-      "eq=1.6*math.pow(10,-19) # charge\n",
-      "h=6.626*math.pow(10,-34) # plank constant\n",
-      "c=3*math.pow(10,8) # speed of light in m/s\n",
-      "y=0.85*math.pow(10,-6) # wavelength in m\n",
-      "R=(n*eq*y)/(h*c) # responsivity in A/W\n",
-      "Ip=2*math.pow(10,-6) # mean photo current\n",
-      "Po=Ip/R   # received optical power in W\n",
-      "re=(n*Po*y)/(h*c)  # number of received photons\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.3f %s' %(\" The responsivity = \",R,\"A/W\"))\n",
-      "print ('%s %.3f %s' %(\"\\n The received optical power = \",Po*math.pow(10,6),\"uW\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The number of received photons = \",re/math.pow(10,13),\"*10^13 photons/sec\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The responsivity =  0.376 A/W\n",
-        "\n",
-        " The received optical power =  5.315 uW\n",
-        "\n",
-        " The number of received photons =  1.25 *10^13 photons/sec\n"
-       ]
-      }
-     ],
-     "prompt_number": 54
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 25: PgNo-494"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable declaration\n",
-      "h=6.625*math.pow(10,-34) # plank constant\n",
-      "c=3*math.pow(10,8) # speed of light in m/s\n",
-      "n=1      # quantum efficiency\n",
-      "eq=1.602*math.pow(10,-19) # charge\n",
-      "E=1.3*math.pow(10,-19) # energy in J\n",
-      "y=(h*c)/E # wavelength in m\n",
-      "M=18      # multiplication factor\n",
-      "rp=math.pow(10,13) # no. of photon per sec\n",
-      "Po=rp*E   # output power in w\n",
-      "Ip=(n*Po*eq)/E   # output photocurrent in A\n",
-      "I=M*Ip     # photocurrent in A\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.3f %s' %(\" The wavelength = \",y*math.pow(10,6),\"um\"))\n",
-      "print ('%s %.1f %s' %(\"\\n The output power = \",Po*math.pow(10,6),\"uW\"))\n",
-      "print ('%s %.3f %s' %(\"\\n The photocurrent = \",I*math.pow(10,6),\"uA\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The wavelength =  1.529 um\n",
-        "\n",
-        " The output power =  1.3 uW\n",
-        "\n",
-        " The photocurrent =  28.836 uA\n"
-       ]
-      }
-     ],
-     "prompt_number": 55
-    },
-    {
-     "cell_type": "heading",
-     "level": 2,
-     "metadata": {},
-     "source": [
-      "Example 26: PgNo-497"
-     ]
-    },
-    {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "import math\n",
-      "\n",
-      "# Variable declaration\n",
-      "e_c=2*math.pow(10,10) # number of electron collected\n",
-      "p=5*math.pow(10,10)  # number of photon incident\n",
-      "n=e_c/p   # quantum efficiency\n",
-      "eq=1.602*math.pow(10,-19) # charge\n",
-      "h=6.626*math.pow(10,-34) # plank constant\n",
-      "c=3*math.pow(10,8)# speed of light in m/s\n",
-      "y=0.85*math.pow(10,-6) # wavelength in m\n",
-      "y1=0.85     # wavelength in um\n",
-      "Eg=(h*c)/y  #  bandgap energy in J\n",
-      "Eg1=1.24/y1 # bandgap energy in terms of eV\n",
-      "Po=10*math.pow(10,-6) # incident power in W\n",
-      "Ip=(n*eq*Po)/Eg   # mean output photocurrent in A\n",
-      "\n",
-      "# Results\n",
-      "print ('%s %.2f %s' %(\" The quantum efficiency = \",n*100,\"%\"))\n",
-      "print ('%s %.3f %s' %(\"\\n The bandgap energy = \",Eg*math.pow(10,19),\"*10^-19 J\"))\n",
-      "print ('%s %.2f %s' %(\"\\n The bandgap energy = \",Eg1,\"eV\"))\n",
-      "print ('%s %.3f %s' %(\"\\n The mean output photocurrent = \",Ip*math.pow(10,6),\"uA\"))"
-     ],
-     "language": "python",
-     "metadata": {},
-     "outputs": [
-      {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        " The quantum efficiency =  40.00 %\n",
-        "\n",
-        " The bandgap energy =  2.339 *10^-19 J\n",
-        "\n",
-        " The bandgap energy =  1.46 eV\n",
-        "\n",
-        " The mean output photocurrent =  2.740 uA\n"
-       ]
-      }
-     ],
-     "prompt_number": 56
-    }
-   ],
-   "metadata": {}
-  }
- ]
-}
-\ No newline at end of file
author	kinitrupti	2017-05-12 18:40:35 +0530
committer	kinitrupti	2017-05-12 18:40:35 +0530
commit	d36fc3b8f88cc3108ffff6151e376b619b9abb01 (patch)
tree	9806b0d68a708d2cfc4efc8ae3751423c56b7721 /Optical_Fiber_Communication
parent	1b1bb67e9ea912be5c8591523c8b328766e3680f (diff)
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