{
"metadata": {
"name": "",
"signature": "sha256:a50462da831719a6431c94babed9d22bf70a3961b6e3e7b72f3c1cbaed2eb5dc"
},
"nbformat": 3,
"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter 6: Optical detectors"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 6.1, Page number 201"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"'''Find the quantum efficiency'''\n",
"\n",
"#Varaible declaration \n",
"re = 4.2*10**6 #EHP's\n",
"rp = 6*10**6 #no. of photons\n",
"lamda = 1200 #wavelength(nm)\n",
"\n",
"#Calculation\n",
"N = re/rp\n",
"\n",
"#Result\n",
"print \"Quantum efficiency =\",N*100,\"%\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Quantum efficiency = 70.0 %\n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 6.2, Page number 201"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"'''Find photocurrent'''\n",
"\n",
"#Varaible declaration \n",
"R = 0.85 #responsivity(A/W)\n",
"Po = 1 #incident power(mW)\n",
"\n",
"#Calculation\n",
"Ip = R*Po\n",
"\n",
"#Result\n",
"print \"Photocurrent =\",Ip,\"mA\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Photocurrent = 0.85 mA\n"
]
}
],
"prompt_number": 3
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 6.3, Page number 201"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"'''Find responsivity of photo diode'''\n",
"\n",
"#Varaible declaration \n",
"E = 0.75*1.6*10**-19 #energy gap(V)\n",
"c = 3*10**8 #speed of light(m/s)\n",
"N = 60./100 #quantum efficiency\n",
"h = 6.62*10**-34 #Planck's constant\n",
"\n",
"#Calculation\n",
"lamda = (h*c)/E\n",
"R = (N*lamda)/1248\n",
"\n",
"#Result\n",
"print \"Responsivity =\",round((R/1E-9),1),\"A/W\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Responsivity = 0.8 A/W\n"
]
}
],
"prompt_number": 4
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 6.4, Page number 202"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"'''Find responsivity and quantum efficiency'''\n",
"\n",
"#Varaible declaration \n",
"re = 1.5*10**12 #EHP's\n",
"rp = 3*10**12 #no. of photons\n",
"lamda = 0.65*10**-6 #wavelength(m)\n",
"h = 6.62*10**-34 #Palnck's constant\n",
"c = 3*10**8 #speed of light(m/s)\n",
"e = 1.6*10**-19 #charge of an electron(C)\n",
"\n",
"#Calculation\n",
"N = re/rp\n",
"\n",
"R = (N*e*lamda)/(h*c)\n",
"\n",
"#Result\n",
"print \"Quantum efficiency =\",N*100,\"%\"\n",
"print \"Responsivity =\",round(R,3),\"A/W\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Quantum efficiency = 50.0 %\n",
"Responsivity = 0.262 A/W\n"
]
}
],
"prompt_number": 6
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 6.5, Page number 202"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"'''Estimate -\n",
"a)operating walength\n",
"b)incident optical power'''\n",
"\n",
"#Varaible declaration \n",
"E = 1.5*10**-19 #photon energy(J)\n",
"c = 3*10**8 #speed of light(m/s)\n",
"N = 65./100 #quantum efficiency\n",
"Ip = 1.5*10**-6 #photocurrent(A)\n",
"h = 6.62*10**-34 #Planck's constant\n",
"c = 3*10**8 #speed of light(m/s)\n",
"e = 1.6*10**-19 #charge of an electron(C)\n",
"\n",
"#Calculations\n",
"#Part a\n",
"lamda = (h*c)/E\n",
"\n",
"#Part b\n",
"f = c/lamda\n",
"R = (N*e)/(h*f)\n",
"Po = Ip/R\n",
"\n",
"#Results\n",
"print \"a)Operating waelength =\",lamda/1E-6,\"um\"\n",
"print \"b)Optical power =\",round((Po/1E-6),2),\"uW\"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"a)Operating waelength = 1.324 um\n",
"b)Optical power = 2.16 uW\n"
]
}
],
"prompt_number": 7
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 6.6, Page number 203"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"'''Find wavelength'''\n",
"\n",
"#Varaible declaration \n",
"Eg = 1.43*1.6*10**-19 #energy gap(V)\n",
"c = 3*10**8 #speed of light(m/s)\n",
"h = 6.62*10**-34 #Planck's constant\n",
"\n",
"#Calculations\n",
"lamda_c = (h*c)/Eg\n",
"\n",
"#Result\n",
"print \"Wavelength =\",round((lamda_c/1E-6),2),\"um\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Wavelength = 0.87 um\n"
]
}
],
"prompt_number": 9
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 6.7, Page number 203"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"'''Find -\n",
"a)responsivity\n",
"b)Optical power received\n",
"c)no. of received photons'''\n",
"\n",
"#Varaible declaration \n",
"N = 50./100 #quantum efficiency\n",
"lamda = 900 #wavelength(nm)\n",
"Ip = 10**-6 #photocurrent(A)\n",
"c = 3*10**8 #speed of light(m/s)\n",
"h = 6.62*10**-34 #Planck's constant\n",
"\n",
"#Calculations\n",
"#Part a\n",
"R = (N*lamda)/1248\n",
"\n",
"#Part b\n",
"Po = Ip/R\n",
"\n",
"#Part c\n",
"n = (Po*lamda*10**-9)/(h*c)\n",
"\n",
"#Results\n",
"print \"a)Responsivity =\",round(R,2),\"A/W\"\n",
"print \"b)Optical power =\",round((Po/1E-6),2),\"*10^-6 W\"\n",
"print \"c)No. of photons =\",round((n/1e+13),3),\"*10^13(Calculation mistake in textbook)\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"a)Responsivity = 0.36 A/W\n",
"b)Optical power = 2.77 *10^-6 W\n",
"c)No. of photons = 1.257 *10^13(Calculation mistake in textbook)\n"
]
}
],
"prompt_number": 11
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 6.8, Page number 204"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"'''Find the multiplication factor of photodiode'''\n",
"\n",
"#Varaible declaration \n",
"N = 80./100 #quantum efficiency\n",
"lamda = 0.9*10**-6 #wavelength(m)\n",
"I = 12*10**-6 #output current(A)\n",
"Po = 0.5*10**-6 #incident power(W)\n",
"c = 3*10**8 #speed of light(m/s)\n",
"h = 6.626*10**-34 #Planck's constant\n",
"e = 1.6*10**-19 #charge of an electron(C)\n",
"\n",
"#Calculations\n",
"R = (N*e*lamda)/(h*c) #responsivity(A/W)\n",
"Ip = Po*R #photocurrent(A)\n",
"M = I/Ip\n",
"\n",
"#Result\n",
"print \"Multiplication factor =\",M"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Multiplication factor = 41.4125\n"
]
}
],
"prompt_number": 12
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 6.9, Page number 205"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"'''Find the responsivity and multiplication factor'''\n",
"\n",
"#Varaible declaration \n",
"N = 65./100 #quantum efficiency\n",
"lamda = 850*10**-9 #wavelength(m)\n",
"I = 10*10**-6 #output current(A)\n",
"Po = 0.5*10**-6 #incident power(W)\n",
"c = 3*10**8 #speed of light(m/s)\n",
"h = 6.626*10**-34 #Planck's constant\n",
"e = 1.6*10**-19 #charge of an electron(C)\n",
"\n",
"#Calculations\n",
"R = (N*e*lamda)/(h*c) #responsivity(A/W)\n",
"\n",
"M = I/(R*Po)\n",
"\n",
"#Result\n",
"print \"Responsiviy =\",round(R,3),\"A/W\"\n",
"print \"Multiplication factor =\",M"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Responsiviy = 0.445 A/W\n",
"Multiplication factor = 44.9728506787\n"
]
}
],
"prompt_number": 13
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 6.10, Page number 205"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"'''Estimate -\n",
"a)noise equivalent power\n",
"b)specific detectivity'''\n",
"\n",
"#Varaible declaration \n",
"N = 55./100 #quantum efficiency\n",
"lamda = 1.3*10**-6 #wavelength(nm)\n",
"Id = 8*10**-9 #dark current(A)\n",
"A = 75*50*10**-12 #dimensions(m)\n",
"c = 3*10**8 #speed of light(m/s)\n",
"h = 6.62*10**-34 #Planck's constant\n",
"\n",
"#Calculations\n",
"#Part a\n",
"NEP = (h*c*((2*e*Id)**0.5))/(N*e*lamda)\n",
"\n",
"#Part b\n",
"D = A**0.5/NEP\n",
"\n",
"#Results\n",
"print \"a)Noise equivalent power =\",round((NEP/1E-14),2),\"*10^-14 W\"\n",
"print \"b)Specific detectivity =\",round((D/1E+8),2),\"*10^8\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"a)Noise equivalent power = 8.78 *10^-14 W\n",
"b)Specific detectivity = 6.97 *10^8\n"
]
}
],
"prompt_number": 14
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 6.11, Page number 206"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"'''Find -\n",
"a)optical gain\n",
"b)CE current'''\n",
"\n",
"#Varaible declaration \n",
"N = 60./100 #quantum efficiency\n",
"lamda = 1.26*10**-6 #wavelength(m)\n",
"Ic = 15*10**-3 #output current(A)\n",
"Po = 125*10**-6 #incident power(W)\n",
"c = 3*10**8 #speed of light(m/s)\n",
"h = 6.626*10**-34 #Planck's constant\n",
"e = 1.6*10**-19 #charge of an electron(C)\n",
"\n",
"#Calculations\n",
"#Part a\n",
"Go = (h*c*Ic)/(lamda*e*Po)\n",
"\n",
"#Part b\n",
"Nfe = Go/N\n",
"\n",
"#Results\n",
"print \"a)Optical gain =\",round(Go,1)\n",
"print \"b)Common emiiter current =\",round(Nfe,1),\"A\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"a)Optical gain = 118.3\n",
"b)Common emiiter current = 197.2 A\n"
]
}
],
"prompt_number": 15
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 6.12, Page number 207"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"'''Calculate the maximum 3dB bandwidth'''\n",
"\n",
"import math\n",
"\n",
"#Variable declaration\n",
"tf = 5*10**-12 #transit time(sec)\n",
"G = 70 #photoconductive gain\n",
"\n",
"#Calculation\n",
"Bm = 1/(2*math.pi*tf*G)\n",
"\n",
"#Result\n",
"print \"The maximum 3dB bandwidth permitted by photoconductor is\",round((Bm/1E+6),1),\"MHz\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The maximum 3dB bandwidth permitted by photoconductor is 454.7 MHz\n"
]
}
],
"prompt_number": 16
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 6.13, Page number 207"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"'''Calculate the output photocurrent'''\n",
"\n",
"#Variable declaration\n",
"rp = 10**11 #no. of photons/sec\n",
"hf = 1.28*10**19 #energy of photons(J)\n",
"e = 1.6*10**-19 #charge of an electron(C)\n",
"\n",
"#Calculations\n",
"Po = rp/hf\n",
"N = 1 #efficiency for an ideal photodiode\n",
"Ip = (N*Po*e)/hf\n",
"\n",
"#Result\n",
"print \"Output photocurrent =\",round((Ip/1E-47),2),\"*10^-47 A(Calculation mistake in textbook)\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Output photocurrent = 9.77 *10^-47 A(Calculation mistake in textbook)\n"
]
}
],
"prompt_number": 17
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 6.14, Page number 207"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"'''Find the output photocurrent'''\n",
"\n",
"#Variable declaration\n",
"R = 0.40 #responsivity(A/W)\n",
"phi = 100 #incident flux(uW/mm^2)\n",
"A = 2 #active area(mm^2)\n",
"\n",
"#Calculations\n",
"Po = phi*A #incident power(uW)\n",
"Ip = R*Po\n",
"\n",
"#Result\n",
"print \"Photocurrent =\",Ip/1e+3,\"mA\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Photocurrent = 0.08 mA\n"
]
}
],
"prompt_number": 5
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 6.15, Page number 208"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"'''Find the multiplication factor of photodiode'''\n",
"\n",
"#Varaible declaration \n",
"N = 50./100 #quantum efficiency\n",
"lamda = 1.3*10**-6 #wavelength(m)\n",
"I = 8*10**-6 #output current(A)\n",
"Po = 0.4*10**-6 #incident power(W)\n",
"c = 3*10**8 #speed of light(m/s)\n",
"h = 6.626*10**-34 #Planck's constant\n",
"e = 1.6*10**-19 #charge of an electron(C)\n",
"\n",
"#Calculations\n",
"R = (N*e*lamda)/(h*c) #responsivity(A/W)\n",
"Ip = Po*R #photocurrent(A)\n",
"M = I/Ip\n",
"\n",
"#Result\n",
"print \"Multiplication factor =\",round(M,2)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Multiplication factor = 38.23\n"
]
}
],
"prompt_number": 19
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 6.16, Page number 208"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"'''Calculate the maximum 3dB bandwidth'''\n",
"\n",
"import math\n",
"\n",
"#Variable declaration\n",
"tf = 4.5*10**-12 #transit time(sec)\n",
"G = 80 #photoconductive gain\n",
"\n",
"#Calculation\n",
"Bm = 1/(2*math.pi*tf*G)\n",
"\n",
"#Result\n",
"print \"The maximum 3dB bandwidth permitted by photoconductor is\",round((Bm/1E+10),4),\"GHz(Calculation mistake in textbook)\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The maximum 3dB bandwidth permitted by photoconductor is 0.0442 GHz(Calculation mistake in textbook)\n"
]
}
],
"prompt_number": 36
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 6.17, Page number 209"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"'''Estimate responsivity and received optical power'''\n",
"\n",
"#Varaible declaration \n",
"N = 50./100 #quantum efficiency\n",
"lamda = 0.9*10**-6 #wavelength(m)\n",
"Ip = 10**-6 #photocurrent(A)\n",
"c = 3*10**8 #speed of light(m/s)\n",
"h = 6.62*10**-34 #Planck's constant\n",
"e = 1.6*10**-19 #charge of an electron(C)\n",
"\n",
"#Calculations\n",
"R = (N*e*lamda)/(h*c)\n",
"\n",
"Po = Ip/R\n",
"\n",
"\n",
"#Results\n",
"print \"Responsivity =\",round(R,2),\"A/W\"\n",
"print \"Optical power =\",round((Po/1E-6),2),\"*10^-6 W\"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Responsivity = 0.36 A/W\n",
"Optical power = 2.76 *10^-6 W\n"
]
}
],
"prompt_number": 20
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 6.18, Page number 209"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"'''Find the efficiency of a PIN silicon photodiode'''\n",
"\n",
"#Varaible declaration \n",
"R = 0.374 #responsivity(A/W)\n",
"lamda = 1300*10**-9 #wavelength(m)\n",
"c = 3*10**8 #speed of light(m/s)\n",
"h = 6.62*10**-34 #Planck's constant\n",
"e = 1.6*10**-19 #charge of an electron(C)\n",
"\n",
"#Calculations\n",
"N = (R*h*c)/(e*lamda)\n",
"\n",
"#Result\n",
"print \"Efficiency =\",round((N*100),1),\"%\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Efficiency = 35.7 %\n"
]
}
],
"prompt_number": 21
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 6.20, Page number 209"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"'''Find the thickness of the intrinsic region'''\n",
"\n",
"#Variable declaration\n",
"A = 1.5*10**-3 #area(mm^2)\n",
"R = 100 #load resistance(Ohms)\n",
"Eo = 1.04*10**-10 #permitivitty for Si(F/m)\n",
"vd = 10**7 #electron saturation velocity(m/s)\n",
"\n",
"#Calculation\n",
"w = (R*Eo*A*vd)**0.5\n",
"\n",
"#Result\n",
"print \"The required thickness is\",round(w/1E-6),\"um(Calculation mistake in textbook)\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The required thickness is 12490.0 um(Calculation mistake in textbook)\n"
]
}
],
"prompt_number": 22
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 6.21, Page number 210"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"'''Find the dark current'''\n",
"\n",
"import math\n",
"\n",
"#Varaible declaration \n",
"N = 64./100 #quantum efficiency\n",
"lamda = 0.85*10**-6 #wavelength(m)\n",
"B = 1 #bandwidth(Hz)\n",
"D = 7*10**10 #specific detectivity(/MHz-W)\n",
"A = 10*10**-6 #dimensions(m)\n",
"c = 3*10**8 #speed of light(m/s)\n",
"h = 6.62*10**-34 #Planck's constant\n",
"e = 1.602*10**-19 #charge of an electron(C)\n",
"\n",
"#Calculations\n",
"Id = ((N*math.sqrt(e*A)*lamda)/(h*c*math.sqrt(2)*D))**0.5\n",
"\n",
"#Result\n",
"print \"Dark current =\",round((Id/1E-3),2),\"mA\"\n",
"#Square root of Id has not been taken in the textbook.Hence, the difference in solution"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Dark current = 5.92 mA\n"
]
}
],
"prompt_number": 6
}
],
"metadata": {}
}
]
}