# Chapter8 - Optoelectronic detectors¶

## Example 8.1 : Page 204¶

In [2]:
from __future__ import division
#The photon energy and optical power
#given data :
print "part (a)"
h=6.626*10**-34## in Js
c=3*10**8## in ms**-1
E=1.52*10**-19## in J
lamda=((h*c)/E)*10**6#
print "The photon energy = %0.2f micro-m "%lamda
print "part (b)"
e=1.6*10**-19## in J
Ip=3*10**6## in A
E=1.52*10**-19## in J
eta=70/100#
R=(eta*e)/E#
P_in=(Ip/R)*10**-6#
print "The optical power = %0.2f micro W "%P_in

part (a)
The photon energy = 1.31 micro-m
part (b)
The optical power = 4.07 micro W


## Example 8.2 : Page 205¶

In [3]:
from __future__ import division
#The quantum efficiency,Maximum possible band gap energy and mean output
#given data :
print "part (a)"
e=1## electron
p=2## photon
eta=(e/p)*100#
print "The quantum efficiency, eta = %0.2f %%"%eta
print "part (b)"
h=6.626*10**-34##in Js
c=3*10**8## in m s**-1
lamda_c=0.85*10**-6## in m
Eg=((h*c)/lamda_c)/1.6*10**19#
print "Maximum possible band gap energy,Eg = %0.2f eV "%Eg
print "part (c)"
e=1## electron
p=2## photon
eta=(e/p)#
e=1.6*10**-19## in J
h=6.626*10**-34##in Js
c=3*10**8## in m s**-1
lamda_c=0.85*10**-6## in m
Eg=((h*c)/lamda_c)#
P_in=10*10**-6## in W
Ip=((eta*e*P_in)/Eg)*10**6#
print "The mean output, Ip = %0.2f micro A"%Ip

part (a)
The quantum efficiency, eta = 50.00 %
part (b)
Maximum possible band gap energy,Eg = 1.46 eV
part (c)
The mean output, Ip = 3.42 micro A


## Example 8.3 : Page 205¶

In [4]:
from __future__ import division
#The quantum efficiency and The responsivity of the diode
#given data :
print "part (a)"
e=2*10**10## in s**-1
p=5*10**10## in s**-1
eta=e/p#
print "The quantum efficiency  = ",eta
print "part (b)"
e=2*10**10## in s**-1
p=5*10**10## in s**-1
eta=e/p#
e=1.6*10**-19## in J
h=6.626*10**-34##in Js
c=3*10**8## in m s**-1
lamda=0.90*10**-6## in m
R=(eta*e*lamda)/(h*c)#
print "The responsivity of the diode,R = %0.2f AW**-1"%R

part (a)
The quantum efficiency  =  0.4
part (b)
The responsivity of the diode,R = 0.29 AW**-1


## Example 8.4 : Page 210¶

In [5]:
from __future__ import division
#The multiplication
#given data :
eta=40/100##
e=1.6*10**-19## in J
h=6.626*10**-34##in Js
c=3*10**8## in m s**-1
lamda=1.3*10**-6## in m
P_in=0.3*10**-6## in W
I=6*10**-6## in A
M=(I*h*c)/(P_in*eta*e*lamda)#
print "The multiplication factor,M = %0.1f"%M

The multiplication factor,M = 47.8


## Example 8.5 : Page 210¶

In [6]:
from __future__ import division
#Photon rate
#given data :
e=1.6*10**-19## in J
M=800#
eta=90/100## quantum efficiency
I=2*10**-9## in A
P_rate=I/(e*eta*M)#
print "Photon incident rate = %0.2e s**-1"%P_rate

Photon incident rate = 1.74e+07 s**-1


## Example 8.6 : Page 212¶

In [7]:
from __future__ import division
from math import pi
#Gain and The output photocurrent
#given data :
print "part (a)"
tf=6*10**-12## in s
del_f=450*10**6## in Hz
G=1/(2*pi*tf*del_f)#
print "the gain = %0.2f"%G
print "part (b)"
tf=6*10**-12## in s
del_f=450*10**6## in Hz
G=1/(2*pi*tf*del_f)#
eta=75/100#
P_in=5*10**-6## in W
e=1.6*10**-19## in J
lamda=1.3*10**-6#
h=6.626*10**-34##in Js
c=3*10**8## in m s**-1
I=(G*eta*P_in*e*lamda)/(h*c)#
print "The output photo-current, I = %0.3e A"%I

part (a)
the gain = 58.95
part (b)
The output photo-current, I = 2.313e-04 A


## Example 8.7 : Page 215¶

In [8]:
from __future__ import division
from math import sqrt
#rms value of shot noise ,dark noise and thermal noise current and S/N ratio
print "part (a)"
n=0.7##efficiency
e=1.6*10**-19##charge
h=1.3##in micro meter
hc=6.626*10**-34##plack constant
c=3*10**8##m/s
pin=500##nW
Ip=((n*e*h*10**-6*pin*10**-9)/(hc*c))##in amperes
df=25##Mhz
f1=1##
is2=(2*e*Ip*df*10**6*f1)##
Is=sqrt(is2)##in amperes
Id=5*10**-9##amperes
id2=(2*e*Id*df*10**6)##
Id=sqrt(id2)##in amperes
k=1.38*10**-23##
t=300##in kelvin
rl=1000##ohms
it2=((4*k*t*df*10**6)/rl)##
it=sqrt(it2)##in amperes
print "rms value of shot noise current is = %0.3f nA"%(Is*10**9)
print "rms value of dark current is = %0.2f nA"%(Id*10**9)
print "rms value of thermal noise current is = %0.2f nA "%(it*10**9)
print "part (b)"
n=0.7##efficiency
e=1.6*10**-19##charge
h=1.3##in micro meter
hc=6.626*10**-34##plack constant
c=3*10**8##m/s
pin=500##nW
Ip=((n*e*h*10**-6*pin*10**-9)/(hc*c))##in amperes
df=25##Mhz
f1=1##
is2=(2*e*Ip*df*10**6*f1)##
Is=sqrt(is2)##in amperes
Id=5*10**-9##amperes
id2=(2*e*Id*df*10**6)##
Id=sqrt(id2)##in amperes
k=1.38*10**-23##
t=300##in kelvin
rl=1000##ohms
it2=((4*k*t*df*10**6)/rl)##
it=sqrt(it2)##in amperes
itt2=is2+id2+it2##in A**2
ip2=Ip**2##
sn=ip2/itt2##
print "S/N ratio = %d"%sn
#S/N ratio is calculated wrong in the textbook

part (a)
rms value of shot noise current is = 1.712 nA
rms value of dark current is = 0.20 nA
rms value of thermal noise current is = 20.35 nA
part (b)
S/N ratio = 321