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{
"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": {}
}
]
}
|
