# Problem in simulation of optically pumped VCSEL rate equation

1. Apr 5, 2009

### vutergoli

this is a optically pumped VCSEL rate equation...

$have to write one editor function dy = qwer(t,y) dy = zeros(2,1); h=6.62e-34; %plank's constant c=3e10; % speed of light La=42e-7; %active layer thickness Ap=154e-10; %pumped area lamda_p=1310e-7; % pump wavelength eta_abs= 0.0243; %pump absorption coefficient A=11e8; %monomolecular recombination coefficient B=8.2e-11; %bimolecular recombination coefficient C=3.5e-29; %Auger recombination coefficient N=6e18;% Carrier density Ntr=1.85e18; %career number at transparency tn=2.5e-9; %career lifetime (s) Bita=3e-5; %spontaneous emission factor ts=3.294e-12; %photon lifetime (s) eV=1e-30; G=2.8522e-6; gamma=0.05; dy(1)=(((h*c*La*Ap)*(A*N+B*N^2+C*N^3))/(lamda_p*eta_abs*eV))-(y(1)/tn)-G*(y(1)-Ntr)*y(2); dy(2)=gamma*G*(y(1)-Ntr)*y(2)-(y(2)/ts)+((Bita*y(1))/tn); end$have to write another editor

tspan = [0 80e-10];
y0 =[0 0 ];

[T,Y] = ode45(@qwer,tspan,y0);

subplot(2,1,1);
plot(T,Y(:,1),'k');
title('carrier densities');
xlabel('time');
ylabel('densities');
subplot(2,1,2);
plot(T,Y(:,2),'k');
title('photon densities');
xlabel('time');
ylabel('densities');

if i run this code i got this(1.jpg) graph..

now i want to replace N to y(1) at dy(1) equation
$have to write one editor function dy = qwer(t,y) dy = zeros(2,1); h=6.62e-34; %plank's constant c=3e10; % speed of light La=42e-7; %active layer thickness Ap=154e-10; %pumped area lamda_p=1310e-7; % pump wavelength eta_abs= 0.0243; %pump absorption coefficient A=11e8; %monomolecular recombination coefficient B=8.2e-11; %bimolecular recombination coefficient C=3.5e-29; %Auger recombination coefficient Ntr=1.85e18; %career number at transparency tn=2.5e-9; %career lifetime (s) Bita=3e-5; %spontaneous emission factor ts=3.294e-12; %photon lifetime (s) eV=1e-30; G=2.8522e-6; gamma=0.05; dy(1)=(((h*c*La*Ap)*(A*y(1)+B*(y(1))^2+C*(y(1))^3))/(lamda_p*eta_abs*eV))-(y(1)/tn)-G*(y(1)-Ntr)*y(2); dy(2)=gamma*G*(y(1)-Ntr)*y(2)-(y(2)/ts)+((Bita*y(1))/tn); end$have to write another editor

tspan = [0 80e-10];
y0 =[0 0 ];

[T,Y] = ode45(@qwer,tspan,y0);

subplot(2,1,1);
plot(T,Y(:,1),'k');
title('carrier densities');
xlabel('time');
ylabel('densities');
subplot(2,1,2);
plot(T,Y(:,2),'k');
title('photon densities');
xlabel('time');
ylabel('densities');

if i run this code i didn't get any graph..

can anyone plz help me..

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