Hello Everybody,(adsbygoogle = window.adsbygoogle || []).push({});

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?

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Calculate Relative intensity noise using laser Rate equations matlab

Can you offer guidance or do you also need help?

Draft saved
Draft deleted

**Physics Forums | Science Articles, Homework Help, Discussion**