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{
"metadata": {
"name": "Chapter_14"
},
"nbformat": 3,
"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": "Chapter 14 : Optical fiber measurements"
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": "Example 14.1, page 912"
},
{
"cell_type": "code",
"collapsed": false,
"input": "import math\n\n#Variable declaration\nv2=10.7 #increased voltage\nv1=2.1 #voltage\nl1=2 #length in Km\nl2=0.002 #length in Km\n\n\n\n#Calculation\na=(10/(l1-l2))*math.log10(v2/v1) #Attenuation\nu=0.2/(l1-l2) #incertainty\n\n#Result\nprint'Attenuation per Km = %.1f dB Km^-1'%a\nprint'Uncertainty = \u00b1 %.1f dB'%u",
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": "Attenuation per Km = 3.5 dB Km^-1\nUncertainty = \u00b1 0.1 dB\n"
}
],
"prompt_number": 4
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": "Example 14.2, page 917"
},
{
"cell_type": "code",
"collapsed": false,
"input": "import math\n\n#Variable declaration\nt2=100 #time in sec\nt1=10 #time in sec\nti=0.525 #micro voltage\nto=0.021 #micro voltage\nC=1.64*10**4 #thermal capacity\ntin=4.3*10**-4 #maximum temperature rise\npop=98*10**-3 #optical power\n\n\n#Calculation\ntc=(t2-t1)/(math.log(ti)-math.log(to)) #time constant for the calorimeter\na=(C*tin)/(pop*tc) #absortion loss\n\n#Result\nprint'Absorption loss in dB = %.1f dB Km^-1'%a",
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": "Absorption loss in dB = 2.6 dB Km^-1\n"
}
],
"prompt_number": 6
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": "Example 14.3, page 919"
},
{
"cell_type": "code",
"collapsed": false,
"input": "import math\n\n#Variable declaration\nVsc=6.14*10**-9 #voltage\nVop=153.38*10**-6 #voltage without scattering\nl=2.92 #length of fibre in cm\n\n\n#Calculation\na=4.343*10**5*Vsc/(l*Vop) #scattering loss\n\n#Result\nprint'Scattering loss in dB = %.1f dB Km^-1'%a",
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": "Scattering loss in dB = 6.0 dB Km^-1\n"
}
],
"prompt_number": 8
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": "Example 14.4, page 922"
},
{
"cell_type": "code",
"collapsed": false,
"input": "import math\n\n#Variable declaration\nt1=12.6*10**-9 #time in sec\nt2=0.3*10**-9 #time in sec\n\n\n\n#Calculation\nt=math.sqrt(t1**2-t2**2)/1.2 #pulse broadening \nBop=0.44/t #bandwidth length product\n\n#Result\nprint'(a) 3dB pulse broadening = %.1f ns km^-1'%(t*10**9)\nprint'(b) Fiber bandwidth\u2013length product = %.1f MHz km'%(Bop*10**-6)",
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": "(a) 3dB pulse broadening = 10.5 ns km^-1\n(b) Fiber bandwidth\u2013length product = 41.9 MHz km\n"
}
],
"prompt_number": 12
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": "Example 14.5, page 940"
},
{
"cell_type": "code",
"collapsed": false,
"input": "import math\n\n#Variable declaration\nA=6.2 #output pattern size\nD=10 #screen position\n\n#Calculation\nNA=A/math.sqrt(A**2+(4*D**2)) #numerical aperture\n\n#Result\nprint'Numerical aperture = %.2f'%NA",
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": "Numerical aperture = 0.30\n"
}
],
"prompt_number": 2
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": "Example 14.6, page 942"
},
{
"cell_type": "code",
"collapsed": false,
"input": "#Variable declaration\nphi=4 #angular velocity\nl=0.1 #length in meter\nwe=300*10**-6 #shadow pulse width\n\n#Calculation\ns=l*phi #shadow velocity\nd=we*s #fibre diameter\n\n#Result\nprint'Outer fibre diameter = %.1f um'%(d*10**6)",
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": "Outer fibre diameter = 120.0 um\n"
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": "Example 14.7, page 950"
},
{
"cell_type": "code",
"collapsed": false,
"input": "import math\n\n#Variable declaration\na=5*10**-3 #optical signal power\nb=20*10**-6 #optical signal power\nc=0.3*10**-3 #optical signal power\nd=800*10**-9 #optical signal power\n\n#Calculation\nadb=10*math.log10(a*10**3) #in dBm\nbdb=10*math.log10(b*10**3) #in dBm\ncdb=10*math.log10(c*10**6) #in dBu\nddb=10*math.log10(d*10**6) #in dBu\n\n#Result\nprint'(a) For a 1 mW reference power level'\nprint' optical signal power of 5 mW = %.2f dBm'%adb\nprint' optical signal power of 20 uW = %.2f dBm'%bdb\nprint'\\n(b) For a 1 \u03bcW reference power level'\nprint' optical signal power of 0.3 mW = %.2f dBu'%cdb #value given in a textbook is incorrect\nprint' optical signal power of 800 nW = %.2f dBu'%ddb",
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": "(a) For a 1 mW reference power level\n optical signal power of 5 mW = 6.99 dBm\n optical signal power of 20 uW = -16.99 dBm\n\n(b) For a 1 \u03bcW reference power level\n optical signal power of 0.3 mW = 24.77 dBu\n optical signal power of 800 nW = -0.97 dBu\n"
}
],
"prompt_number": 35
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": "Example 14.8, page 953"
},
{
"cell_type": "code",
"collapsed": false,
"input": "import math\n\n#Variable declaration\nNA=0.02 #numerical aperture\nyr=0.7*10**-3 #Rayleigh scattering coefficient\nc=2.998*10**8 #speed of light\nwo=50*10**-9 #pulse time\nn1=1.5\n\n#Calculation\np=0.5*(((NA**2)*yr*wo*c)/(4*(n1**3))) #power ratio\npdb=10*math.log10(p*10**3) #in dB\n\n#Result\nprint'Power ratio = %.3f X 10^-7'%(p*10**7) #value given in a textbook is incorrect\nprint'Power ratio in dB = %.1f dB'%pdb #value given in a textbook is incorrect",
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": "Power ratio = 1.555 X 10^-7\nPower ratio in dB = -38.1 dB\n"
}
],
"prompt_number": 19
}
],
"metadata": {}
}
]
}
|
