{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Chapter10 - Optical Fiber Systems"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Ex:10.1 Page No: 412"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "The voltage required to have a pi radian phase change  = 4.56 volt\n"
     ]
    }
   ],
   "source": [
    "from __future__ import division\n",
    "r=30.8*10**-12## electro optice coefficient in m/V\n",
    "L=3*10**-2## length in m\n",
    "y=1.3*10**-6## wavelength in m\n",
    "n=2.1#\n",
    "d=30*10**-6## distance between the electrodes in m\n",
    "V=(y*d)/((n)**3*r*L)## voltage required to have a pi radian phase change in volt\n",
    "print \"The voltage required to have a pi radian phase change  = %0.2f volt\"%( V)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Ex:10.2 Page No: 412"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "The total channel loss =31 dB\n"
     ]
    }
   ],
   "source": [
    "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",
    "print \"The total channel loss =%d dB\"%( CL)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Ex:10.3 Page No: 413"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "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 = 6.00 dB\n",
      "\n",
      " without mode coupling, equalization penalty = 0.03 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"
     ]
    }
   ],
   "source": [
    "from math import sqrt\n",
    "p=0.5*10**-9## pulse broadening in s/km\n",
    "L=12## length in km\n",
    "Pt=p*sqrt(L)## with mode coupling, the total rms broadening in s\n",
    "BT=20*10**6##\n",
    "DL=2*(2*Pt*BT*sqrt(2))**4## dispersion equalization penalty in dB\n",
    "Pt1=p*L## without mode coupling, the total rms broadening in s\n",
    "DL1=2*(2*Pt1*BT*sqrt(2))**4## without mode coupling, equalization penalty in dB\n",
    "DL2=2*(2*Pt1*150*10**6*sqrt(2))**4## without mode coupling,dispersion equalization penalty with 125 Mb/s\n",
    "DL3=2*(2*Pt*125*10**6*sqrt(2))**4## with mode coupling,dispersion equalization penalty with 125 Mb/s\n",
    "print \"with mode coupling, the total rms broadening = %0.2f ns\"%( Pt*10**9)#\n",
    "print \"\\n The dispersion equalization penalty = %0.2f dB\"%( DL*10**4)#\n",
    "print \"\\n without mode coupling, the total rms broadening = %0.2f dB\"%( Pt1*10**9)#\n",
    "print \"\\n without mode coupling, equalization penalty = %0.2f dB\"%( DL1)#\n",
    "print \"\\n without mode coupling,dispersion equalization penalty with 125 Mb/s = %0.2f dB\"%( DL2)#\n",
    "print \"\\n with mode coupling,dispersion equalization penalty with 125 Mb/s = %0.2f dB\"%( DL3)#\n",
    "print \"\\n The answer is wrong in the textbook\""
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Ex:10.4 Page No: 414"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "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"
     ]
    }
   ],
   "source": [
    "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",
    "print \"The length when system operating at 25 Mbps = %0.2f km\"%( L)#\n",
    "print \"\\n The length when system operating at 350 Mbps = %0.2f km\"%( L1)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Ex:10.5 Page No: 414"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "The fider loss = 20.00 dB\n",
      "\n",
      " The total splicing loss = 3.20 dB\n",
      "\n",
      " The fangle effects & future splice = 5.00 dB\n",
      "\n",
      " The total attenuation = 29.20 dB\n",
      "\n",
      " The excess power margin = 2.80 dB\n",
      "\n",
      " hence the system can operate with small excess power margin\n"
     ]
    }
   ],
   "source": [
    "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",
    "print \"The fider loss = %0.2f dB\"%( fl)#\n",
    "print \"\\n The total splicing loss = %0.2f dB\"%( tl)#\n",
    "print \"\\n The fangle effects & future splice = %0.2f dB\"%( ae)#\n",
    "print \"\\n The total attenuation = %0.2f dB\"%( ta)#\n",
    "print \"\\n The excess power margin = %0.2f dB\"%( Ep)#\n",
    "print \"\\n hence the system can operate with small excess power margin\""
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Ex:10.6 Page No: 415"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "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"
     ]
    }
   ],
   "source": [
    "from math import log\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#\n",
    "L=(Ps-Pr-Ls-4*Lc-(10*log(N))/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*log(N1))/log(10)-sm)/(2*af)## max transmission length in km when reflection star coupler is used\n",
    "print \"The max transmission length when transmission star coupler is used = %0.2f km\"%( L)#\n",
    "print \"\\n The max transmission length when reflection star coupler is used = %0.2f km\"%( L1)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Ex:10.7 Page No: 416"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "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"
     ]
    }
   ],
   "source": [
    "from math import sqrt\n",
    "y=860*10**-9## wavelength in m\n",
    "L=5000## length in m\n",
    "X=0.024#\n",
    "dy=20*10**-9## spectral width in m\n",
    "dts=6*10**-9## silica optical link rise time in s\n",
    "dtr=8*10**-9## detector rise in s\n",
    "c=3*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*10**-12## intermodel dispersion in s/m\n",
    "dti=id*L## intermodel dispersion delay time\n",
    "dtsy=sqrt((dts**2)+(dtr**2)+(dtm**2)+(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",
    "print \"The system rise time = %0.2f ns\"%( dtsy*10**9)#\n",
    "print \"\\n The max bit rate for NRZ coding = %0.2f Mbit/s\"%( Br_max/10**6)#\n",
    "print \"\\n The max bit rate for RZ coding = %0.2f Mbit/s\"%( Br_max1/10**6)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Ex:10.8 Page No: 417"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "The transmission distance for Si fiber = 71.43 m\n",
      "\n",
      " The transmission distance for GRIN fiber = 420.00 m\n"
     ]
    }
   ],
   "source": [
    "Br=50*10**6## data rate in b/s\n",
    "c=3*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*n1**2)/(2*n1*n12*Br)## transmission distance for GRIN fiber\n",
    "print \"The transmission distance for Si fiber = %0.2f m\"%( L_si)#\n",
    "print \"\\n The transmission distance for GRIN fiber = %0.2f m\"%( L_GI)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Ex:10.9 Page No: 417"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "The material dispersion limited transmission distance =627 m\n"
     ]
    }
   ],
   "source": [
    "Br=20.0*10**6## data rate in b/s\n",
    "c=3*10**8## speed of light in m/s\n",
    "y=86*10**-9## wavelength in m\n",
    "dy=30*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",
    "print \"The material dispersion limited transmission distance =%d m\"%( Lmax)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Ex:10.10 Page No: 418"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "The material dispersion limited distance = 12.54*10**10*1/Br m\n",
      "\n",
      " The model dispersion limited distance = 2.10*10**10*1/Br m\n",
      "\n",
      " The attenuation limited distance =60-20log(Br) km\n"
     ]
    }
   ],
   "source": [
    "from __future__ import division\n",
    "y=860*10**-9## wavelength in m\n",
    "c=3*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## loss a in dB/m\n",
    "Pr=-65## receiver power in dB\n",
    "Pt=-5## transmitted power in dB\n",
    "dy=30*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",
    "print \"The material dispersion limited distance = %0.2f*10**10*1/Br m\"%( Lmax/10**10)#\n",
    "print \"\\n The model dispersion limited distance = %0.2f*10**10*1/Br m\"%( L_GI/10**10)#\n",
    "print \"\\n The attenuation limited distance =%d-20log(Br) km\"%( L_At/10**3)"
   ]
  }
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