Hi everyone
I have no problem with error line codes. However my problem is when I try to plot the result, it doesn't show anything, just straight line at y = 0.
This is my code, thanks for your help.
clearclcti = 0; tf = 3E-8; tspan=[ti tf]; y0=[0; 0; 0]; %y(1) = Photon Density
%y(2) = Inverted Population Density
%y(3) = Photocarrier Density
[t,y] = ode45(@rate_eq,tspan,y0);figure(1); hold on plot(t,y(:,1)); title('Photon Density'); xlabel('Time'); ylabel('Photon Density'); hold off figure(2); hold on plot(t,y(:,2)); title('Inverted Population Density '); xlabel('Time'); ylabel('Inverted Population Density'); hold off figure(3); hold on plot(t,y(:,3)); title('Photocarrier Density'); xlabel('Time'); ylabel('Photocarrier Density'); hold off function dy = rate_eq( t,y )%Rate equation for Q-switched fiber laser.
dy = zeros(3,1);% Planck constant (m^2kg/s)
h = 6.62606957E-34;% Speed of light
c = 299792458;% Dissipative optical loss
delta = 0.4;%Inversion reduction factor
gamma = 1.8;% Length of total fiber (m)
lr = 15;% Length of active fiber (m)
L = 3;% Thickness of the SA (m)
Lsa = 1E-5;% Output coupling ratio
R = 0.95;% Stimulated emission area (m2)
sigmaes = 2E-25;% Spontataneous decay time(t)
tg = 1E-2;% Saturation photocarrier density
Nsa = 2.4E27;% SA carrier recombination time (s)
tsa = 0.1E-9;% nonsaturable loss (s)
lambdans = 0.4;% modulation depth
lambdas = 0.1;% Effective doping area of active fiber (m2)
A = 1.26E-11;% Pumping power (W)
Pp = 2E-2;% Wavelength of signal light (m)
lambdaP = 1530E-9;% Frequency of signal (Hz)
v = c/lambdaP;% Round trip transit time (Hz)
tr = lr/c;% Pumprate of active medium
Wp = Pp/(h*v*A*L);% Saturable absorption
lambdana = (lambdas/(1+(y(3)/Nsa)))+lambdans;%lambdana = 0.5;
% Change of Photon density
dy(1) = (y(1)/tr)*(2*sigmaes*y(2)*L-2*lambdana*Lsa+log(R)-delta);% Change of Population Inversion density
dy(2) = Wp-gamma*sigmaes*c*y(1)*y(2)-(y(2)/tg);% Change of Photocarrier density
dy(3) = c*y(1)*lambdana-(y(3)/tsa);end
Best Answer