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Laser rate equation using matlab

  1. May 29, 2014 #1
    Hi, is there anyone familiar with rate equation solving using Matlab? I need help on this
     
  2. jcsd
  3. May 29, 2014 #2

    DrClaude

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    Staff: Mentor

    Hi mya, welcome to PF!

    You need to be more specific. What equation are you trying to solve? What exactly is the problem you are having?
     
  4. Jun 1, 2014 #3
    I need to plot the light-current characteristic of laser (Pout vs I) by solving using ode45.

    dy(1)= ((ni*I)/(q*V))-(N/tau)-(v_g*a*((N-N_tr)/(1+epsilon*N_p))*N_p);
    dy(2)= (T*v_g*a*((N-N_tr)/(1+epsilon*N_p))*N_p) + (B_sp*T*R_sp) - (N_p/tau_p);

    Pout = N_p*Vp*h*v*alpha_m*v_g;

    how can I do that?
     
  5. Jun 2, 2014 #4

    I need to plot the light-current characteristic of laser (Pout vs I) by solving using ode45.

    dy(1)= ((ni*I)/(q*V))-(N/tau)-(v_g*a*((N-N_tr)/(1+epsilon*N_p))*N_p);
    dy(2)= (T*v_g*a*((N-N_tr)/(1+epsilon*N_p))*N_p) + (B_sp*T*R_sp) - (N_p/tau_p);

    Pout = N_p*Vp*h*v*alpha_m*v_g;

    how can I do that?
     
  6. Jun 2, 2014 #5

    DrClaude

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    Staff: Mentor

    I'm sorry, but this is not clear at all. You have dy(1) and dy(2), but I don't see any y(1) or y(2). And these are the derivatives with respect to what? And how does Pout relate to those ODEs?
     
  7. Jun 2, 2014 #6
    sorry for that y(1) = N, y(2) = N_p. How can I plot the Pout vs current? Pout is related to N_p by solving the ODE
     
  8. Jun 9, 2014 #7

    DrClaude

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    Staff: Mentor

    I'm sorry, but I'm still not clear on what you are solving. Are the derivatives with respect to time?
     
  9. Jun 10, 2014 #8
    rate equation

    clc
    clear all
    close all
    tau_s = 3e-9;
    N0 = 1e24;
    A =1e-12;
    P0 = 1/(A*tau_s);
    TSPAN = [0 10];
    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') % carriers density in high laser level
    subplot(2,1,2)
    plot(T*tau_s ,Y(:,2)*P0)
    title('photons density in activer region') % photons density in activer region
    And this is the 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 ( try: from I0 to 3*I0 for example ...and see what happens!)
    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))
     
    Last edited: Jun 10, 2014
  10. Jun 10, 2014 #9
    I hope that it would be helpful,

    Can any one help me by giving MATLAB code to simulate semiconductor laser rate equation by finite difference methord. i wrote a code but it is not working. please help me.
     
  11. Jun 13, 2014 #10
    qzsas
     
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