Chapter 13: Optical networks¶
Example 13.1, Page Number: 464¶
In [1]:
import math
import numpy as np
#variable declaration
N=np.array([5,10,50]) #number of station
alpha = 0.4 #attanuation (dB/km)
L_tap = 10 #coupling loss (dB)
L_thru = 0.9 #coupler throughput(dB)
Li = 0.5 #intrinsic coupler loss(dB)
Lc = 1.0 #coupler to fiber loss(dB)
L = 0.5 #link length(km)
#calculation
fiber_Loss = alpha *L #fiber loss(dB)
Pbudget = N*(alpha*L+2*Lc+Li+ L_thru)-alpha*L-2*L_thru +2* L_tap #power budget(dB)
#result
print "Fiber loss at 500m =",fiber_Loss,"dB"
print "Power budget of three stations 5, 10, 50 respectively = ",Pbudget[0],"dB",Pbudget[1],"dB",Pbudget[2],"dB"
Example 13.2, Page Number: 465¶
In [4]:
import math
import matplotlib.pyplot as plt
import numpy as np
import scipy as sp
from scipy import special
%matplotlib inline
#variable declaration
alpha = 0.4 #attanuation (dB/km)
L_tap = 10 #coupling loss (dB)
L_thru = 0.9 #coupler throughput(dB)
Li = 0.5 #intrinsic coupler loss(dB)
Lc = 1.0 #coupler to fiber loss(dB)
L = 0.5 #link length(km)
Pbudget_LED = 38 #power loss of LED
Pbudget_LASER = 51 #power loss of LASER
#calculation
N_LED = (Pbudget_LED + alpha*L-2*L_thru-2*L_tap)/(alpha*L+2*Lc+Li+L_thru)
N_LASER = (Pbudget_LASER + alpha*L-2*L_thru-2*L_tap)/(alpha*L+2*Lc+Li+L_thru)
#result
print "Number of stations allowed for given loss of 38 dB with LED source =",round(N_LED,0)
print "Number of stations allowed for given loss of 51 dB with LASER source =",round(N_LASER,0)
#plot
x1=arange(0.0, 50.0, 10.0)
Pbudget1 = x1*(alpha*L+2*Lc+Li+ L_thru)-alpha*L-2*L_thru +2* L_tap
plot(x1,Pbudget1)
title('Plot of total power loss as a function of number attached station for linear bus')
ylabel('Power loss between station 1 and N(dB)')
xlabel('Number of stations')
text(30,120,'Linear bus')
Out[4]:
Example 13.3, Page Number: 465¶
In [5]:
import math
import numpy as np
#variable declaration
N=np.array([5,10]) #number of station
alpha = 0.4 #attanuation (dB/km)
L_thru = 0.9 #coupler throughput(dB)
Li = 0.5 #intrinsic coupler loss(dB)
Lc = 1.0 #coupler to fiber loss(dB)
L = 0.5 #link length(km)
#calculation
DR = (N-2)*(alpha*L+2*Lc+Li+L_thru) #dynamic range(dB)
#result
print "Dynamic range for number of station 5 = ",DR[0],"dB"
print "Dynamic range for number of station 10 = ",DR[1],"dB"
Example 13.4, Page Number: 466¶
In [14]:
import math
#variable declaration
N1=10 #number of station
N2=50 #number of station
alpha = 0.4 #attanuation (dB/km)
L = 0.5 #link length(km)
Lc = 1.0 #coupler to fiber loss(dB)
Lexcess1 = 0.75 #excess loss for 10 station
Lexcess2 = 1.25 #excess loss for 50 station
#calculation
Ps_Pr1 = Lexcess1+alpha*2*L+2*Lc+10*math.log10(N1) #power margin for 10 station(dB)
Ps_Pr2 = Lexcess2+alpha*2*L+2*Lc+10*math.log10(N2) #power margin for 50 station(dB)
#result
print "Power margin between transmitter and receiver for 10 station =",round(Ps_Pr1,1),"dB"
print "Power margin between transmitter and receiver for 50 station =",round(Ps_Pr2,1),"dB"
Example 13.5, Page Number: 477¶
In [15]:
import math
#variable declaration
L_OM2 = 40 #Length of OM2 fiber(meter)
L_OM3 = 100 #Length of OM3 fiber(meter)
BW_OM2 = 500*10**6 #bandwidth of OM2 fiber(MHz)
BW_OM3 = 2000*10**6 #bandwidth of OM3 fiber(MHz)
#calculation
Lmax = L_OM2*(BW_OM3/BW_OM2)+L_OM3 #Maximum link length(meter)
#result
print "Maximum link length = ",Lmax,"m"