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{
"metadata": {
"name": "",
"signature": "sha256:435dc2503f7ab5f5c4bb167df36c6ef12f8211207bc52e60997787c4d2bd8d5c"
},
"nbformat": 3,
"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"12: Holography and Fibre Optics"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example number 12.1, Page number 271"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
" \n",
"#importing modules\n",
"import math\n",
"from __future__ import division\n",
"\n",
"#Variable declaration\n",
"n1 = 1.43; #Refractive index of fibre core\n",
"n2 = 1.4; #Refractive index of fibre cladding\n",
"\n",
"#Calculation\n",
"#As sin (alpha_c) = n2/n1, solving for alpha_c\n",
"alpha_c = math.asin(n2/n1); #Critical angle for optical fibre(rad)\n",
"alpha_c = alpha_c*57.2957795; #Critical angle for optical fibre(degrees)\n",
"alpha_c = math.ceil(alpha_c*10**3)/10**3; #rounding off the value of alpha_c to 3 decimals\n",
"#AS cos(theta_c) = n2/n1, solving for theta_c\n",
"theta_c = math.acos(n2/n1); #Critical propagation angle for optical fibre(rad)\n",
"theta_c = theta_c*57.2957795; #Critical propagation angle for optical fibre(degrees)\n",
"theta_c = math.ceil(theta_c*10**2)/10**2; #rounding off the value of theta_c to 2 decimals\n",
"NA = math.sqrt(n1**2 - n2**2); #Numerical aperture for optical fibre\n",
"NA = math.ceil(NA*10**3)/10**3; #rounding off the value of NA to 3 decimals\n",
"\n",
"#Result\n",
"print \"The critical angle for optical fibre is\",alpha_c, \"degrees\"\n",
"print \"The critical propagation angle for optical fibre is\",theta_c, \"degrees\"\n",
"print \"Numerical aperture for optical fibre is\",NA\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The critical angle for optical fibre is 78.244 degrees\n",
"The critical propagation angle for optical fibre is 11.76 degrees\n",
"Numerical aperture for optical fibre is 0.292\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example number 12.2, Page number 271"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
" \n",
"#importing modules\n",
"import math\n",
"from __future__ import division\n",
"\n",
"#Variable declaration\n",
"n1 = 1.45; #Refractive index of fibre core\n",
"n2 = 1.4; #Refractive index of fibre cladding\n",
"\n",
"#Calculation\n",
"NA = math.sqrt(n1**2 - n2**2); #Numerical aperture for optical fibre\n",
"NA = math.ceil(NA*10**4)/10**4; #rounding off the value of NA to 4 decimals\n",
"#As sin(theta_a) = sqrt(n1^2 - n2^2), solving for theta_a\n",
"theta_a = math.asin(math.sqrt(n1**2 - n2**2)); #Half of acceptance angle of optical fibre(rad)\n",
"theta_a = theta_a*57.2957795; #Half of acceptance angle of optical fibre(degrees)\n",
"theta_accp = 2*theta_a; #Acceptance angle of optical fibre(degrees)\n",
"theta_accp = math.ceil(theta_accp*10**2)/10**2; #rounding off the value of theta_accp to 2 decimals\n",
"Delta = (n1 - n2)/n1; #Relative refractive index difference\n",
"Delta = math.ceil(Delta*10**4)/10**4; #rounding off the value of Delta to 4 decimals\n",
"\n",
"#Result\n",
"print \"Numerical aperture for optical fibre is\", NA\n",
"print \"The acceptance angle of optical fibre is\",theta_accp, \"degrees\"\n",
"print \"Relative refractive index difference is\", Delta\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Numerical aperture for optical fibre is 0.3775\n",
"The acceptance angle of optical fibre is 44.36 degrees\n",
"Relative refractive index difference is 0.0345\n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example number 12.3, Page number 271"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
" \n",
"#importing modules\n",
"import math\n",
"from __future__ import division\n",
"\n",
"#Variable declaration\n",
"n1 = 1.55; #Refractive index of fibre core\n",
"n2 = 1.53; #Refractive index of fibre cladding\n",
"n0 = 1.3; #Refractive index of medium\n",
"\n",
"#Calculation\n",
"NA = math.sqrt(n1**2 - n2**2); #Numerical aperture for optical fibre\n",
"NA = math.ceil(NA*10**4)/10**4; #rounding off the value of NA to 4 decimals\n",
"#n0*sin(theta_a) = sqrt(n1^2 - n2^2) = NA, solving for theta_a\n",
"theta_a = math.asin(math.sqrt(n1**2 - n2**2)/n0); #Half of acceptance angle of optical fibre(rad)\n",
"theta_a = theta_a*57.2957795; #Half of acceptance angle of optical fibre(degrees)\n",
"theta_accp = 2*theta_a; #Acceptance angle of optical fibre(degrees)\n",
"\n",
"#Result\n",
"print \"Numerical aperture for step index fibre is\",NA\n",
"print \"The acceptance angle of step index fibre is\",int(theta_accp), \"degrees\"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Numerical aperture for step index fibre is 0.2482\n",
"The acceptance angle of step index fibre is 22 degrees\n"
]
}
],
"prompt_number": 5
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example number 12.4, Page number 271 Theoritical proof"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example number 12.5, Page number 272"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
" \n",
"#importing modules\n",
"import math\n",
"from __future__ import division\n",
"\n",
"#Variable declaration\n",
"alpha = 2; #Power loss through optical fibre(dB/km)\n",
"P_in = 500; #Poer input of optical fibre(micro-watt)\n",
"z = 10; #Length of the optical fibre(km)\n",
"\n",
"#Calculation\n",
"#As alpha = 10/z*log10(P_in/P_out), solving for P_out\n",
"P_out = P_in/10**(alpha*z/10); #Output power in fibre optic communication(micro-Watt)\n",
"\n",
"#Result\n",
"print \"The output power in fibre optic communication is\",P_out, \"micro-Watt\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The output power in fibre optic communication is 5.0 micro-Watt\n"
]
}
],
"prompt_number": 6
},
{
"cell_type": "code",
"collapsed": false,
"input": [],
"language": "python",
"metadata": {},
"outputs": []
}
],
"metadata": {}
}
]
}
|
