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   "source": [
    "# Chapter6 - Optical fiber cables and connections"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example 6.1 : Page 119"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {
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   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "refractive index = 1.59\n"
     ]
    }
   ],
   "source": [
    "from __future__ import division\n",
    "#refractive index\n",
    "l=0.47##in db\n",
    "nf=10**((l/-10))##\n",
    "from sympy import symbols, solve\n",
    "x=symbols(\"x\")\n",
    "p=1+-2.22*x+x**2##\n",
    "y=solve(p,x)##\n",
    "print \"refractive index = %0.2F\"%y[1]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example 6.2 : Page 121"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "part (a)\n",
      "insertion loss at the joint = 0.64 dB\n",
      "part (b)\n",
      "insertion loss at the joint = 0.286 dB\n"
     ]
    }
   ],
   "source": [
    "from math import log10, acos, pi\n",
    "#loss\n",
    "print \"part (a)\"\n",
    "dya=0.1##\n",
    "n1=1.50##refrative index\n",
    "na=1##\n",
    "k1=n1/n1##\n",
    "k2=1##\n",
    "nf=((16*(n1)**2)/((n1+1)**4))##\n",
    "nlat=(2/(3.14))*(acos(dya/2)-(dya/2)*(1-(dya/2)**2)**(1/2))##\n",
    "nt=nf*nlat##\n",
    "lt=(-10*log10(nt))##in dB\n",
    "print \"insertion loss at the joint = %0.2f dB\"%lt\n",
    "print \"part (b)\"\n",
    "dya=0.1##\n",
    "n1=1.50##refrative index\n",
    "na=1##\n",
    "k1=n1/n1##\n",
    "k2=1##\n",
    "nf=((16*(n1)**2)/((n1+1)**4))##\n",
    "nlat=(2/(pi))*(acos(dya/2)-(dya/2)*(1-(dya/2)**2)**(1/2))#\n",
    "nt=k2*nlat##\n",
    "lt=(-10*log10(nt))##in dB\n",
    "print \"insertion loss at the joint = %0.3f dB\"%lt"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example 6.3 : Page 122"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "total loss = 0.75 dB\n"
     ]
    }
   ],
   "source": [
    "from math import sqrt\n",
    "#loss\n",
    "d=100##micro meter\n",
    "dx=0##\n",
    "dy=3##in micro mete\n",
    "dth=3##in degree\n",
    "dthr=dth*(pi/180)##\n",
    "dya=0.02##\n",
    "n1=1.48##refrative index\n",
    "na=1##\n",
    "k1=n1/n1##\n",
    "k2=1##\n",
    "nf=((16*(n1)**2)/((n1+1)**4))##\n",
    "nlat=(2/(pi))*(acos(dy/100)-(dy/100)*(1-(dy/100)**2)**(1/2))##\n",
    "NA=n1*(sqrt(2*dya))##\n",
    "nang=((1-(na*dthr)/(pi*NA)))##\n",
    "nt=nf*nlat*nang##\n",
    "lt=(-10*log10(nt))##in dB\n",
    "print \"total loss = %0.2f dB\"%lt"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example 6.4 : Page 124"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "total loss = 4.1260 dB\n"
     ]
    }
   ],
   "source": [
    "from scipy import log10\n",
    "#loss\n",
    "d1=80##micro meter\n",
    "na1=0.25##\n",
    "alpha1=2##\n",
    "d2=60##in micro meter\n",
    "na2=0.21##\n",
    "alpha2=1.9##\n",
    "ncd=(d2/d1)**2##\n",
    "nna=(na2/na1)**2##\n",
    "nalpha=((1+(2/alpha1))/(1+((2/alpha2))))##\n",
    "nt=ncd*nna*nalpha##\n",
    "lt=(-10*log10(nt))##in dB\n",
    "print \"total loss = %0.4f dB\"%lt"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example 6.5 : Page 125"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "total loss forward direction = 3.52 dB\n",
      "total loss backward direction = 0.217 dB\n"
     ]
    }
   ],
   "source": [
    "#loss\n",
    "d1=60##micro meter\n",
    "na1=0.25##\n",
    "alpha1=2.1##\n",
    "d2=50##in micro meter\n",
    "na2=0.20##\n",
    "alpha2=1.9##\n",
    "ncd=(d2/d1)**2##\n",
    "nna=(na2/na1)**2##\n",
    "nalpha1=1##\n",
    "nalpha=((1+(2/alpha1))/(1+((2/alpha2))))##\n",
    "ncd1=1##\n",
    "nna1=1##\n",
    "nt=ncd*nna*nalpha1##\n",
    "ltf=(-10*log10(nt))##in dB\n",
    "nt1=ncd1*nna1*nalpha##\n",
    "ltb=(-10*log10(nt1))##in dB\n",
    "print \"total loss forward direction = %0.2f dB\"%ltf\n",
    "print \"total loss backward direction = %0.3f dB\"%ltb"
   ]
  }
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