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%Script
% Define model parameters
temperature = 25;
wavelength = 1.312e-6;
parameters.frequency = 3e8/wavelength;
parameters.I = 18e-3;
parameters.e = 1.602e-19;
parameters.V = 9e-11;
parameters.tau_n = 3e-9;
parameters.tau_p = 1e-12;
parameters.beta_sp = 4e-4;
parameters.g_po = 3e-6;
parameters.g_comp = 3.4e-17;
parameters.N_t = 1.2e18;
parameters.total_quantum_efficiency = 0.2;
parameters.plancksconstant = 6.624e-34;
parameters.optical_conFactor = 0.2;
% Set initial conditions and time span
y0 = [1e15; 0;];
tspan = [0 1e-9];
% Vary injection current values
injection_current_values = linspace(0, 20e-3, 3585);% Example: Varying from 0 to 1 mA
Power = zeros(size(injection_current_values))'; %%%%%%%%%%%%%
Phase = zeros(size(injection_current_values))'; %%%%%%%%%%%%%
% Solve the rate equations for each injection current value
for i = 1:length(injection_current_values)
% Set the current injection
parameters.input_power = injection_current_values(i);
% Solve the differential equations
[t, y] = ode45(@(t, y) laserRateEquations(t, y, parameters), tspan, y0);
Phase(i) = (2.981/2)*(parameters.optical_conFactor*parameters.g_po*(y(i,1)- ... %%%%%%%%%%%%%
parameters.N_t)-(1/parameters.tau_p));
Power(i) = (y(i,2)*parameters.V*parameters.total_quantum_efficiency* ...
parameters.plancksconstant*parameters.frequency)/ ...
(2*parameters.optical_conFactor*parameters.tau_p);%Output Power
end
figure
subplot(2,1,1)
plot(t,Phase),grid
xlabel('t'),ylabel('Phase')
subplot(2,1,2)
plot(t,Power),grid
xlabel('t'),ylabel('Power')
%Laser Rate Equation Function
function dydt = laserRateEquations(~, y, parameters)
% Lang-Kobayashi model for carrier density (N) and photon density (S)
I = parameters.I;
e = parameters.e;
V = parameters.V;
tau_n = parameters.tau_n;
tau_p = parameters.tau_p;
beta_sp = parameters.beta_sp;
g_po = parameters.g_po;
g_comp = parameters.g_comp;
N_t = parameters.N_t;
% Rate equations
dydt = zeros(2, 1);
dydt(1) = I/(e*V) - (y(1)/tau_n) - g_po*((y(1) - N_t)/(1+y(2)))*y(2); %Carrier Density (N)
dydt(2) = g_po*((y(1) - N_t)/(1+g_comp*y(2)))*y(2) ...
- (y(2)/tau_p) + (beta_sp*(y(1)/tau_n)); %Photon Density (S)
end