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{
"metadata": {
"name": "Chapter_5"
},
"nbformat": 3,
"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": "Chapter 5 : Optical fiber connection: joints, couplers and isolators"
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": "Example 5.1, page 220"
},
{
"cell_type": "code",
"collapsed": false,
"input": "import math\n\n#Variable declaration\nn1=1.5 #core refractive index\nn=1.0 #refractive index of medium\n\n#Calculation\nr=((n1-n)/(n1+n))**2 #magnitude of the Fresnel reflection at the fiber\u2013air interface\nLoss=-10*math.log10(1-r) #loss in decibels at the single interface\nLoss1=2*Loss #total loss\n\n#Result\nprint'Total loss due to Fresnel reflection = %.2f dB'%Loss1 #loss due to fresnel resolution = 0.18X2 dB\n",
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": "Total loss due to Fresnel reflection = 0.35 dB\n"
}
],
"prompt_number": 2
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": "Example 5.2, page 224"
},
{
"cell_type": "code",
"collapsed": false,
"input": "import math\n\n#Variable declaration\nn1=1.5 #refractive index\ny=5 #lateral offset of the fiber core axes in um\na=25 #radius in um\n\n#Calculation\nb=(16*n1**2)/(math.pi*(1+n1)**4)\nc=math.acos(y*(2*a)**-1)\ne=(y*a**-1)\nf=math.sqrt(1-(y*(2*a)**-1)**2)\nn=b*((2*c)-(e*f)) #coupling efficiency \nLoss=-10*math.log10(n) #insertion loss\nna=(math.pi**-1)*((2*c)-(e*f))\nLoss1=-10*math.log10(na) \n\n#Result\nprint'(a) Insertion loss = %.3f dB'%Loss\nprint'(b) Insertion loss = %.2f dB'%Loss1",
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": "(a) Insertion loss = 0.945 dB\n(b) Insertion loss = 0.59 dB\n"
}
],
"prompt_number": 3
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": "Example 5.3, page 226"
},
{
"cell_type": "code",
"collapsed": false,
"input": "import math\n\n#Variable declaration\ny=3 #lateral misalignment in um\na=25 #core radius in um\n\n#Calculation\nLt=0.85*(y*a**-1) #misalignment loss for guided modes\nn=1-Lt #coupling efficiency\nLoss=-10*math.log10(n) #insertion loss\nLt1=0.75*(y*a**-1) #both guided and leaky modes \nn1=1-Lt1 #coupling efficiency\nLoss1=-10*math.log10(n1) #insertion loss\n\n#Result\nprint'(a) Uniform illumination of all guided modes only = %.2f dB'%Loss\nprint'(b) Uniform illumination of all guided and leaky modes = %.2f dB'%Loss1",
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": "(a) Uniform illumination of all guided modes only = 0.47 dB\n(b) Uniform illumination of all guided and leaky modes = 0.41 dB\n"
}
],
"prompt_number": 4
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": "Example 5.4, page 227"
},
{
"cell_type": "code",
"collapsed": false,
"input": "import math\n\n#Variable declaration\nNA=0.2 #numerical aperture\nn1=1.48 #core refractive index\nang=(5*math.pi)/180 #angular misalignment (radians)\nNA1=0.4 #numerical aperture\n\n#Calculation\nna=((16*(n1)**2)/((1+n1)**4))*(1-(ang/(math.pi*NA))) #angular coupling efficiency\nLoss=-10*math.log10(na) #insertion loss\nna1=((16*(n1)**2)/((1+n1)**4))*(1-(ang/(math.pi*NA1))) #angular coupling efficiency\nLoss1=-10*math.log10(na1) #insertion loss\n\n#Result\nprint'Insertion loss at a joint (NA = 0.2) = %.2f dB'%Loss\nprint'Insertion loss at a joint (NA = 0.4) = %.2f dB'%Loss1 #in textbook, value is not calculated",
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": "Insertion loss at a joint (NA = 0.2) = 0.98 dB\nInsertion loss at a joint (NA = 0.4) = 0.64 dB\n"
}
],
"prompt_number": 5
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": "Example 5.5, page 231"
},
{
"cell_type": "code",
"collapsed": false,
"input": "import math\n\n#Variable declaration\nV=2.4 #normalized frequency\na=4 #core radius in um\nNA=0.1 #numerical aperture \nn1=1.46 #core refractive index\ny=1 #lateral misalignment in um\nteta=math.pi/180 #angular misalignment in rad\n\n#Calculation\nw=a*(0.65+(1.62/V**1.5)+(2.88/V**6))/(2**0.5) #normalized spot size\nTl=2.17*(y/w)**2 #loss due to the lateral offset\nTa=2.17*((teta*w*n1*V)/(a*NA))**2 #loss due to angular misalignment\nTt=Tl+Ta #total insertion loss\n\n#Result\nprint'Total insertion loss = %.2f dB'%Tt",
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": "Total insertion loss = 0.72 dB\n"
}
],
"prompt_number": 6
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": "Example 5.6, page 232"
},
{
"cell_type": "code",
"collapsed": false,
"input": "import math\n\n#Variable declaration\nw01=5.6 #mode-field radius in um\nw02=4.2 #mode-field radius in um\n\n#Calculation\nLoss=-10*math.log10(4*((w02/w01)+(w01/w02))**(-2)) #intrinsic loss \n\n#Result\nprint'Intrinsic loss = %.2f dB'%Loss",
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": "Intrinsic loss = 0.35 dB\n"
}
],
"prompt_number": 7
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": "Example 5.7, page 262"
},
{
"cell_type": "code",
"collapsed": false,
"input": "import math\n\n#Variable declaration\np1=60 #input port power\np2=0.004 #output port power\np3=26 #output port power\np4=27.5 #output port power\n\n\n#Calculation\nxloss=10*math.log10(p1/(p3+p4)) #Excess Loss\niloss1=10*math.log10(p1*p3**-1) #Insertion Loss at input\niloss2=10*math.log10(p1/p4) #Insertion Loss at output\ncross=10*math.log10(p2/p1) #Crosstalk ratio\nsrat=((p3/(p3+p4))*100) #Split ratio\n\n#Result\nprint'Excess Loss = %.1f dB'%xloss\nprint'Insertion Loss at input = %.2f dB'%iloss1\nprint'Insertion Loss at output = %.2f dB'%iloss2\nprint'Crosstalk ratio = %.1f dB'%cross\nprint'Split ratio = %.1f percent'%srat",
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": "Excess Loss = 0.5 dB\nInsertion Loss at input = 3.63 dB\nInsertion Loss at output = 3.39 dB\nCrosstalk ratio = -41.8 dB\nSplit ratio = 48.6 percent\n"
}
],
"prompt_number": 8
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": "Example 5.8, page 266"
},
{
"cell_type": "code",
"collapsed": false,
"input": "import math\n\n#Variable declaration\nN=32 #total no of ports\npi=10**3 #optical power at input in micro-watt\npj=14 #optical power at input in micro-watt\n\n\n#Calculation\nsloss=10*math.log10(N) #splitting loss\nxloss=10*math.log10(pi*(pj*N)**-1) #excess loss\ntloss=sloss+xloss #total loss\niloss=10*math.log10(pi*pj**-1) #insertion loss\n\n#Result\nprint'Total loss = %.2f dB'%tloss\nprint'Insertion loss = %.2f dB'%iloss\n",
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": "Total loss = 18.54 dB\nInsertion loss = 18.54 dB\n"
}
],
"prompt_number": 9
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": "Example 5.9, page 268"
},
{
"cell_type": "code",
"collapsed": false,
"input": "import math\n\n#Variable declaration\np=16 #output ports\nl=0.2 #excess loss with split ratio of 50%\nl1=0.1 #splice loss\n\n#Calculation\nm=math.log(p)/math.log(2) #no of stages\nxloss=(4*l)+(3*l1) #excess loss\nsloss=10*math.log10(p) #split loss\niloss=sloss+xloss #insertion loss\n\n#Result\nprint'Insertion loss = %.2f dB'%iloss",
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": "Insertion loss = 13.14 dB\n"
}
],
"prompt_number": 10
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": "Example 5.10, page 277"
},
{
"cell_type": "code",
"collapsed": false,
"input": "#Variable declaration\nh=1.55*10**-6 #optical signal wavelength\nN=1.46 #refractive index\n\n\n#Calculation\nv=h/(2*N) #grating period of the FBG\n\n#Result\nprint'Grating period of FBG = %.2f um'%(v*10**6)",
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": "Grating period of FBG = 0.53 um\n"
}
],
"prompt_number": 11
},
{
"cell_type": "code",
"collapsed": false,
"input": "",
"language": "python",
"metadata": {},
"outputs": [],
"prompt_number": 11
}
],
"metadata": {}
}
]
}
|
