Calculate Relative intensity noise using Rate equations


by mido41854
Tags: equations, intensity, noise, rate, relative
mido41854
mido41854 is offline
#1
Dec5-12, 11:00 AM
P: 2
Hello Everybody,

I'm trying to plot the frequency spectrum of RIN using Matlab.

I've the following code

function p=rateblock
tau_s = 3e-9;
N0 = 1e24;
A =1e-12;
P0 = 1/(A*tau_s);

TSPAN = 0:1e-2:10.23;;
Y0 =[0 0];

[T,Y] = ODE45(@rate_equation,TSPAN,Y0);
subplot(2,1,1)
plot(T*tau_s ,Y(:,1)*N0)
title('carriers density in high laser level')
subplot(2,1,2)
plot(T*tau_s ,Y(:,2)*P0)
title('photons density in activer region') %

dt=1e-2;
s_avg=sum(Y(:,2))/1024;%average photon numbers
ds=Y(:,2)-s_avg;%photon fluctuation with respect to average
TT=1e-6; %total time of integration
N=1024;%fft length
F=[0:N-1]';
RIN=((dt^2)/((s_avg)^2*TT)).*(abs(fft(ds))).^2;
RIN=10*log10(RIN);
plot(F,RIN)
title('RIN')

And for the Rate equation i used this function
function dy = rate_equation(t,y)
dy = zeros(2,1);

tau_s = 3e-9; % carriers lifetime
tau_p = 1e-12; % photons lifetime
A = 1e-12; % linear gain costant
N0 = 1e24; % trasparency carries density
V = 3.75e-14; % modal volume
gamma = 1e-5; % gain compression factor
q = 1.6e-19; % electron charge

I0 = N0*q*V/tau_s; % trasparency current
tau_norm = tau_s/tau_p;
eta = A*tau_p*N0; % efficiency

I = 2.5*I0; % pumping current

dy(1)= I/I0 -y(2)*(y(1) - 1) -y(1);
dy(2) = tau_norm*(y(2)*(eta*(y(1) - 1) -1) + gamma*eta*y(1))


Although I'm facing problems with caluclating the RIN and plot it with frequency ...

Can anybody help me with this issue?
Phys.Org News Partner Science news on Phys.org
Going nuts? Turkey looks to pistachios to heat new eco-city
Space-tested fluid flow concept advances infectious disease diagnoses
SpaceX launches supplies to space station (Update)

Register to reply

Related Discussions
Rate of Noise in Three Sensors Advanced Physics Homework 1
noise measurement-decrease in sound intensity with distance Electrical Engineering 4
Noise Intensity Introductory Physics Homework 1
Relative intensity changing with temperature? General Physics 1
Intensity and Relative Amplitude General Physics 7