{
 "metadata": {
  "name": "Chapter3"
 },
 "nbformat": 3,
 "nbformat_minor": 0,
 "worksheets": [
  {
   "cells": [
    {
     "cell_type": "heading",
     "level": 1,
     "metadata": {},
     "source": "3: Fibre Optics and Applications"
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": "Example number 3.1, Page number 84"
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": "#importing modules\nimport math\n\n#Variable declaration\nn1 = 1.5;          #refractive index of core\nn2 = 1.47;         #refractive index of cladding\nn0 = 1;            #refractive index of air\na = 180/math.pi;        #conversion factor of radian to degree\n\n#Calculation\nNA = math.sqrt((n1**2)-(n2**2));     #numerical aperture\nNA=math.ceil(NA*10)/10;   #rounding off to 1 decimal\nalpha_m = math.asin(NA/n0);         #acceptance angle(radian)\nalpha_m = alpha_m*a;                #acceptance angle(degrees)\nalpha_m=math.ceil(alpha_m*10**2)/10**2;   #rounding off to 2 decimals\nphi_m = math.asin(NA/n1);           #phase angle(radian)\nphi_m = phi_m*a;                    #phase angle(degrees)\nphi_m=math.ceil(phi_m*10**2)/10**2;   #rounding off to 2 decimals\ntheta_c = math.asin(n2/n1);         #critical angle(radian)\ntheta_c = theta_c*a;                #critical angle(degrees)\ntheta_c=math.ceil(theta_c*10**3)/10**3;   #rounding off to 3 decimals\n\n#Result\nprint \"numerical aperture is\",NA\nprint \"acceptance angle is\",alpha_m,\"degrees\"\nprint \"phase angle is\",phi_m,\"degrees\"\nprint \"critical angle is\",theta_c,\"degrees\"",
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": "numerical aperture is 0.3\nacceptance angle is 17.46 degrees\nphase angle is 11.54 degrees\ncritical angle is 78.522 degrees\n"
      }
     ],
     "prompt_number": 3
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": "Example number 3.2, Page number 85"
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": "#importing modules\nimport math\n\n#Variable declaration\nn1 = 1.5;          #refractive index of core\nn2 = 1.47;         #refractive index of cladding\nc = 3*10**8;       #velocity of light(m/sec)\n\n#Calculation\ndeltatbyL = (n1/n2)*((n1-n2)/c);\n\n#Result\nprint \"pulse broadening per unit length is\",deltatbyL,\"s/m\"",
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": "pulse broadening per unit length is 1.02040816327e-10 s/m\n"
      }
     ],
     "prompt_number": 2
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": "Example number 3.3, Page number 85"
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": "#importing modules\nimport math\n\n#Variable declaration\nphi_m = 11.54;       #phase angle(degrees)\na = 0.5*10**-4;\nx = math.pi/180;       #conversion factor from degrees to radians\n\n#Calculation\nphi_m = phi_m*x;      #phase angle(radian)\nL = a/math.tan(phi_m);      #length(m)\nn = 1/(2*L);          #total number of internal reflections(m-1)\n\n#Result\nprint \"alpha = 0 rays have no reflection. hence there are zero reflections for 1 metre.\"\nprint \"alpha = alpha_m rays have\",int(n),\"m-1 internal reflections\"\nprint \"answer given in the book is wrong\"",
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": "alpha = 0 rays have no reflection. hence there are zero reflections for 1 metre.\nalpha = alpha_m rays have 2041 m-1 internal reflections\nanswer given in the book is wrong\n"
      }
     ],
     "prompt_number": 7
    }
   ],
   "metadata": {}
  }
 ]
}