{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Chapter20 Fibre Optic Communication"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example 20.2.1,Pg.no.753"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 12,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "The numerical aperture is 0.35\n",
      "The acceptance angle is 0.36\n"
     ]
    }
   ],
   "source": [
    "import math\n",
    "from math import sqrt\n",
    "n1=1.55  #RI of glass\n",
    "n2=1.51  #RI of clad\n",
    "#NA of the fibe is given as\n",
    "NA=n1*sqrt(2*(n1-n2)/n1)\n",
    "NA=round(NA,2)\n",
    "print 'The numerical aperture is',NA\n",
    "#Acceptance angle is given as\n",
    "acc_angle=math.asin(NA)\n",
    "acc_angle=round(acc_angle,2)\n",
    "print 'The acceptance angle is',acc_angle"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example 20.2.2,Pg.no.761"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 13,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "The V number is 69.12\n",
      "the approximate no . of modes are 2388.8\n"
     ]
    }
   ],
   "source": [
    "import math\n",
    "from math import pi\n",
    "d=50*10**-6\n",
    "wav=0.8*10**-6\n",
    "NA=0.352 \n",
    "#Determination of V number\n",
    "V=(pi)*d*NA/wav\n",
    "V=round(V,2)\n",
    "print 'The V number is',V\n",
    "#Determination of approximate number of modes\n",
    "N=(V**2)/2\n",
    "N=round(N,1)\n",
    "print 'the approximate no . of modes are',N"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example 20.2.3,Pg.no.762"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 14,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "The v number is 4.2291\n",
      "From the table it is seen that 6 modes have cut off v less than 4.23\n"
     ]
    }
   ],
   "source": [
    "import math\n",
    "from math import pi\n",
    "d=5*10**-6\n",
    "wave=1.3*10**-6\n",
    "NA=0.35\n",
    "#Determination of V number\n",
    "V=(pi)*d*NA/wave\n",
    "V=round(V,4)\n",
    "print 'The v number is',V\n",
    "print 'From the table it is seen that 6 modes have cut off v less than 4.23'"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example 20.2.4,Pg.no.763"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 32,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "No . of modes supported by graded index fiber= 1195\n"
     ]
    }
   ],
   "source": [
    "import math\n",
    "a=2     #gradding profile index\n",
    "V=69.1  #normalized cutoff frequency\n",
    "N=2390  #number of modes supported as a step index fiber\n",
    "#Determination of no . of modes supported by graded index fiber\n",
    "N_a=(N*a)/(a+2)\n",
    "print 'No . of modes supported by graded index fiber=',N_a"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example 20.2.5,Pg.no.763"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 30,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "a) the normilized index difference is 0.002\n",
      "b) cladding index required is 1.55\n",
      "The max acceptance angle is 0.1\n"
     ]
    }
   ],
   "source": [
    "import math\n",
    "from math import pi\n",
    "d=10*10**-6\n",
    "wav=1.3*10**-6\n",
    "n1=1.55\n",
    "V_max=2.405\n",
    "NA=(V_max*wav)/(pi*d)\n",
    "#a) Determination of maximum normailized index difference\n",
    "del1=(0.5)*((NA/n1)**2)\n",
    "del1=round(del1,3)\n",
    "print 'a) the normilized index difference is',del1\n",
    "#b) Determination of r effective index of claddin glass\n",
    "n2=n1*(1-del1)\n",
    "n2=round(n2,2)\n",
    "print 'b) cladding index required is',n2\n",
    "#Determination of the fiber acceptance angle\n",
    "theta_max=math.asin(NA)\n",
    "theta_max=round(theta_max,3)\n",
    "print'The max acceptance angle is',theta_max"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example 20.3.1,Pg.no.766"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 29,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "a)The repeater dist for 0.9um wavelength is 12 km\n",
      "b)The repeater dist for 1.5um wavelength is 83.33 km\n"
     ]
    }
   ],
   "source": [
    "import math\n",
    "A_max=25\n",
    "A1=2\n",
    "A2=0.3\n",
    "#a) Determination of repeater dist at 0.9um wavelength\n",
    "z1=A_max/A1\n",
    "print 'a)The repeater dist for 0.9um wavelength is',z1,'km'\n",
    "#b) Determination of repeater dist at 1.5um wavelength\n",
    "z2=A_max/A2\n",
    "z2=round(z2,2)\n",
    "print 'b)The repeater dist for 1.5um wavelength is',z2,'km'"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example 20.4.1,Pg.no.772"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 28,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "The intermodal dispersion is 1.37e-07 s/km\n",
      "The intermodal dispertion for l=12.5 is 1.71e-09 s\n"
     ]
    }
   ],
   "source": [
    "import math\n",
    "#given\n",
    "n1=1.55\n",
    "del1=0.0258\n",
    "l=12.5\n",
    "z=1000\n",
    "c=3*10**8    #velocity of light\n",
    "#a) Determination of intermodal dispersion\n",
    "del_per_km=(n1*z*del1)/((1-del1)*c)*10**7\n",
    "del_per_km=round(del_per_km,2)*10**-7\n",
    "print 'The intermodal dispersion is',del_per_km ,'s/km'\n",
    "#b) Determination of intermodal dispersion for l =12.5\n",
    "del_l=del_per_km*l/1000*10**9\n",
    "del_l=round(del_l,2)*10**-9\n",
    "print 'The intermodal dispertion for l=12.5 is',del_l,'s'"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example 20.4.2,Pg.no.773"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 19,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "The intermodal dispersion is 5.37e-05 sec\n"
     ]
    }
   ],
   "source": [
    "import math\n",
    "n1=1.55\n",
    "del1=(258.0)*(10**-2)\n",
    "z=1000\n",
    "c=3*10**8\n",
    "z_disp=12.5\n",
    "del_graded=(n1*z*del1**2)/(8*c)\n",
    "#Determination of intermodal dispersion\n",
    "del_total=del_graded*z_disp*10**5\n",
    "del_total=round(del_total,2)*10**-5\n",
    "print 'The intermodal dispersion is',del_total,'sec'"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example 20.4.3,Pg.no.774"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 20,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "The total material dispersion is -2.8125 ns\n"
     ]
    }
   ],
   "source": [
    "import math\n",
    "#given\n",
    "wav_0=0.8*10**-6\n",
    "Dm=-0.15\n",
    "wav_3=1.5\n",
    "z=12.5\n",
    "del_t=Dm*wav_3\n",
    "#Determination of total material dispersion\n",
    "del_md=del_t*z\n",
    "print 'The total material dispersion is',del_md,'ns' "
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example 20.4.4,Pg.no.775"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 21,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Expected waveguide dispersion is 495.0 ps\n"
     ]
    }
   ],
   "source": [
    "import math\n",
    "#given\n",
    "Dm=6.6\n",
    "z=12.5\n",
    "del_3=6\n",
    "del_wg=Dm*z*del_3\n",
    "print'Expected waveguide dispersion is',del_wg,'ps'"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example 20.4.5,Pg.no.776"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 27,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "The total dispersion is 1.0 ns\n",
      "The max allowed bit rate is 500.0 Mbps\n"
     ]
    }
   ],
   "source": [
    "import math\n",
    "#given\n",
    "del_imd=0\n",
    "del_md=2.81\n",
    "del_wgd=0.495\n",
    "t_w=2.5\n",
    "del_tot=((del_imd**2)+(del_md**2)+(del_wgd**2))**(1/2)\n",
    "print 'The total dispersion is',del_tot,'ns'\n",
    "t_r=((t_w**2)+(del_tot**2))**(1/2) \n",
    "#Determination of max allowed bit rate\n",
    "B=(1000/(2*t_r))\n",
    "print 'The max allowed bit rate is',B,'Mbps'"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example 20.4.6,Pg.no.778"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 23,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "a)The BW distance product for fiber is 0.125 Mbps−km\n",
      "b)The disp limited length for a fiber is 12.5 km\n"
     ]
    }
   ],
   "source": [
    "import math\n",
    "#given\n",
    "del_t=4.0\n",
    "B=10.0\n",
    "#a) Determination of BW distance product\n",
    "BDP=1/(2*del_t)\n",
    "print'a)The BW distance product for fiber is',BDP,'Mbps−km'\n",
    "#b) Determiation of dispersion limited length\n",
    "z_max_disp=BDP/(B*10**-3)\n",
    "print'b)The disp limited length for a fiber is',z_max_disp,'km'"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example 20.5.1,Pg.no.780"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 24,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "a) i) the wavelength is 0.7 um\n",
      "a) ii) the freq is 459307010.5 MHz\n",
      "b) i) the wavelength is 0.85 um\n",
      "b) ii) the freq is 352941176.471 MHz\n",
      "c)i) the wavelength is 1.3 um\n",
      "c)ii) the freq is 230620467.4 MHz\n"
     ]
    }
   ],
   "source": [
    "import math\n",
    "E1=1.9\n",
    "E2=1.46\n",
    "E3=0.954\n",
    "eV=1.9       #All in eV\n",
    "c=3*10**8    #speed of light\n",
    "#a) Determination of wavelength and freq for E1=1.9\n",
    "wav1=1.241/E1\n",
    "f1=c/(wav1)\n",
    "wav1=round(wav1,1)\n",
    "f1=round(f1,1)\n",
    "print 'a) i) the wavelength is',wav1,'um'\n",
    "print 'a) ii) the freq is',f1,'MHz'\n",
    "#b) Determination of wavelength and freq for E2=1.46\n",
    "wav2=1.241/E2\n",
    "f2=c/(wav2)\n",
    "print 'b) i) the wavelength is',wav2,'um'\n",
    "print 'b) ii) the freq is',f2,'MHz'\n",
    "#c ) Determination of wavelength and freq for E3=0.945\n",
    "wav3=1.241/E3\n",
    "f3=c/(wav3)\n",
    "wav3=round(wav3,1)\n",
    "f3=round(f3,1)\n",
    "print'c)i) the wavelength is',wav3,'um'\n",
    "print'c)ii) the freq is',f3,'MHz'"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example 20.8.1,Pg.no.799"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 25,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "a) the loss−limited fiber is 17.75 km\n",
      "b) the max BW for loss−limited length is 0.022 Gbps\n",
      "the dispertion limited length is 11.32 km\n"
     ]
    }
   ],
   "source": [
    "import math\n",
    "#given\n",
    "pt=0\n",
    "pr=-57\n",
    "Nc=2\n",
    "BER=10**-9\n",
    "N=5\n",
    "Lpt=6\n",
    "Lpr=6\n",
    "Lc=1\n",
    "Ls =0.5\n",
    "Lf=2\n",
    "M=5\n",
    "del_t=0.505\n",
    "B=35\n",
    "Ns=5\n",
    "#a) Determination of loss−limited fiber length\n",
    "z=(pt-pr-M-(Nc*Lc)-(Ns*Ls)-Lpt-Lpr)/Lf\n",
    "print 'a) the loss−limited fiber is',z,'km'\n",
    "#b) Determination of max BW for loss−limited fiber length\n",
    "B_max=1/(5*del_t*z)\n",
    "B_max=round(B_max,3)\n",
    "print 'b) the max BW for loss−limited length is',B_max,'Gbps'\n",
    "#c ) Determination of dispersion−limited length\n",
    "z_disp=1000/(5*del_t*B)\n",
    "z_disp=round(z_disp,2)\n",
    "print 'the dispertion limited length is',z_disp,'km'"
   ]
  }
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