{ "metadata": { "name": "", "signature": "sha256:36c911cea36773d62dbfdfd257319508866d11b39912270afd0ba3c55a7245e6" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 1, "metadata": {}, "source": [ "Chepter 5: Power launching and coupling" ] }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 5.1, Page Number: 192" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "\n", "#variable declartion\n", "phi = 0 #lateral coordinate(degree)\n", "Half_power = 10 #half power beam width(degree)\n", "\n", "#calculation\n", "teta = Half_power/2\n", "teta_rad = teta/57.3\n", "L = math.log(0.5)/math.log(math.cos(teta_rad)) #power distribution co-efficient\n", "\n", "#result\n", "print \"Power distribution co-efficient L = \" ,round(L)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Power distribution co-efficient L = 182.0\n" ] } ], "prompt_number": 14 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 5.2, Page Number: 194" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "\n", "#variable declartion\n", "rs = 35.0*1e-6 #the source radius (meter)\n", "a = 25.0*1e-6 #the core radius of stepindex fiber (meter)\n", "NA = 0.20 #the numerical aperture value\n", "Bo = 150.0*1e4 #radiance ( W/cm^2 * sr)\n", "\n", "#calculation\n", "Ps = ((math.pi**2)*(rs**2))*Bo #power emitted by the source\n", "PLED_step = Ps*(NA**2) #for larger core fiber(W)\n", "PLED_step1 = (((a/rs)**2)*Ps)*(NA**2) #for smaller core fiber at the end face(W)\n", "\n", "#result\n", "print \"For larger core fiber optical power emitted from the LED light source = \" , round(PLED_step*1e3,3),\"mW\"\n", "print \"For smaller core fiber then area optical power coupled to step index fiber on W = \" , round(PLED_step1*1e3,3),\"mW\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "For larger core fiber optical power emitted from the LED light source = 0.725 mW\n", "For smaller core fiber then area optical power coupled to step index fiber on W = 0.37 mW\n" ] } ], "prompt_number": 1 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 5.3, Page Number: 194" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "\n", "#variable declartion\n", "n1 = 3.6 #refractive index of optical source\n", "n = 1.48 #refractive index of silica fiber\n", "\n", "#calculation\n", "R = ((n1-n)/(n1+n))**2 #fresnel reflection\n", "L = -10*(math.log10(1-R)) #power loss(dB)\n", "\n", "#result\n", "print\"Fresnel reflection = \",round(R,3),\" = \",round(R*100,1),\"%\"\n", "print\"Power loss = \" , round(L,2),\"dB\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Fresnel reflection = 0.174 = 17.4 %\n", "Power loss = 0.83 dB\n" ] } ], "prompt_number": 16 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 5.4, Page Number: 205" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "\n", "#variable declartion\n", "a =1*1e-6 #core radii (meters)\n", "d = 0.3*a #axial offset\n", "\n", "#calculation\n", "PT_P = (2/math.pi)*(math.acos(d/(2*a))-(1-(d/(2*a))**2)**0.5*(d/(6*a))*(5-0.5*(d/a)**2)) \n", "PT_P_dB = 10*(math.log10(PT_P)) #power coupled between two fibers(dB)\n", "\n", "#result\n", "print \"Power coupled between two graded index fibers = \" , round(PT_P_dB,2),\"dB\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Power coupled between two graded index fibers = -1.26 dB\n" ] } ], "prompt_number": 17 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 5.5, Page Number: 211" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "\n", "#variable declartion\n", "V = 2.4 #normalized frequency\n", "n1 = 1.47 #core refractive index\n", "n2 = 1.465 #cladding refractive index\n", "a = (9.0/2.0)*10**-6 #core radii (meters)\n", "d = 1*10**-6 #lateral offset (meters)\n", "\n", "#calculation\n", "W = a*(0.65+1.619*V**(-1.5)+2.879*V**-6) #mode field diameter (um)\n", "Lsm = -10*(math.log10(math.exp(-(d/W)**2))) #Loss between identical fibers(dB)\n", "\n", "#result\n", "print \"Mode field diameter = \" , round(W*1e6,2),\"um\"\n", "print \"Loss between single mode fibers due to lateral misalignment = \" , round(Lsm,2),\"dB\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Mode field diameter = 4.95 um\n", "Loss between single mode fibers due to lateral misalignment = 0.18 dB\n" ] } ], "prompt_number": 2 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 5.6, Page Number: 212" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "\n", "#variable declartion\n", "V = 2.4 #normalized frequency\n", "n1 = 1.47 #core refractive index\n", "n2 = 1.465 #cladding refractive index\n", "a = (9.0/2.0)*1e-6 #coreradii in meters\n", "d = 1*1e-6 #lateral offset (m)\n", "teta = 1 #in (degrees)\n", "teta = 1/57.3 #in (radaians) \n", "\n", "#calculation\n", "W = a*(0.65+1.619*V**(-1.5)+2.879*V**-6) #mode field diameter\n", "Lam_bda = 1300.0*10**-9 #wavelength (m)\n", "Lsm_ang = -10*(math.log10(math.exp(-(math.pi*n2*W*teta/Lam_bda)**2))) #(dB)\n", "\n", "#result\n", "print \"Loss between single mode fibers due to angular misalignment = \",round(Lsm_ang,2),\"dB\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Loss between single mode fibers due to angular misalignment = 0.41 dB\n" ] } ], "prompt_number": 3 } ], "metadata": {} } ] }