# Chapter 16 :Soliton Communication Systems¶

## Example 16.1 , Page no:325¶

In :
import math
from __future__ import division

#initialisation of variables
lambda1=850;  #operating wavelength in nm
Beta2=-1;  #dispersion regime ps^2/Km
Gama=2;  #nonlinearity in /W-Km
TFWHM=10;  #fundamental soliton width in ps

#CALCULATIONS
To=TFWHM/1.763;  #pulse width in ps
Ppeak=1/(Gama*(To**2));  #peak power in W

#RESULTS
print"Peak power required to maintain fundamental soliton=",round(Ppeak*10**3,5),"mW";  #multiplication by 10^3 is to convert the unit from w to mW

Peak power required to maintain fundamental soliton= 15.54084 mW


## Example 16.2 , Page no:325¶

In :
import math
from __future__ import division

#initialisation of variables
lambda1=1.55;  #operating wavelength in um
Beta2=-1;  #dispersion regime ps^2/Km
B=10;  #bitrate in Gb/s
two_qo=12;  #separation between two neighbouring solitons in normalized units

#CALCULATIONS
LT=3.14*math.exp(two_qo/2)/(8*(two_qo/2)**2*abs(Beta2)*10**-24)/(B**2*(10**18));  #distance transmission limit in Km

#RESULTS
print"For 10Gb/s bit rate , transmission distance is limited to =",round(LT,5),"Km";
print"the answer is different because of rounding off ";

For 10Gb/s bit rate , transmission distance is limited to = 43984.94485 Km
the answer is different because of rounding off


## Example 16.3 , Page no:325¶

In :
import math
from __future__ import division

#initialisation of variables
alpha=0.2;  #fiber loss in dB/Km
LA=50;  #Amplifier spacing in Km

#CALCULATIONS
G=(alpha*LA);  #gain in fiber
PbyPo=G*math.log(G)/(G-1);  #Multiple of power required by single soliton

#RESULTS
print"Multiple of power required by single soliton =",round(PbyPo,5);
print"the answer is slightly varing due to rounding error";

Multiple of power required by single soliton = 2.55843
the answer is slightly varing due to rounding error


## Example 16.4 , Page no:326¶

In :
import math
from __future__ import division

#initialisation of variables
lambda1=1.55;  #operating wavelength in um
LA=50;  #Amplifier spacing in Km
qo=6;  #Half of separation between two neighbouring solitons in normalized units
Beta2=-1;  #dispersion regime ps^2/Km

#CALCULATIONS
B=1/(4*(qo)**2*abs(Beta2));  #bandwidth in THz

#RESULTS
print"Communication Link bitrate is limited to =",round(B*10**3,5),"GHz";  #Multiplication by 10^3 to convert unit fron THz to GHz

Communication Link bitrate is limited to = 6.94444 GHz


## Example 16.5 , Page no:326¶

In :
import math
from __future__ import division

#initialisation of variables
LT=10000;  #Transmission distance in Km
alpha=0.2;  #fiber loss in dB/Km
lambda1=1.55*10**-6;  #operating wavelength in m
Gama=2;  #nonlinearity in /W-Km
LA=50;  #Amplifier spacing in Km
D=1;  #dispersion parameter ps/(Km-nm)
FG=3.518;  #Fiber gain factor
fj=0.1;  #timing jitter factor
h=6.62607004 * 10-34;  #planck's constant in m2 kg / s
nsp=2;  #spontaneous emission factor
qo=6;  #Half of separation between two neighbouring solitons in normalized units

#CALCULATIONS
B1=((9*3.14*fj**2*LA)/(nsp*FG*qo*lambda1*h*Gama*D*10**-3));  #variable converting la
B2=B1**(1/3);  #variable
B=B2/LT;  #bandwidth in THz

#RESULTS
print"Communication Link bitrate is limited to =",round(B*10**3,5),"Gb/s";  #Multiplication by 10^3 to convert unit fron THz to GHz

Communication Link bitrate is limited to = 14.9581 Gb/s