I have written a Matlab code which is a simulation of NOT gate implementation using ring lasers. Si variable is input in my code. But my code works only for Si = 0. for any other non zero value it doesn't show output.

Vg = 7.5e9; % group velocity

Vp = 3e-11; %Photon reservoir volume

V = 1e-11; %Carrier reservoir Volume

tau_p = 1.7e-12; % photon lifetime

beta = 1e-5; % spontateous emission coefficient

eps = 7.5e-17; % Nonlinear gain suppression coefficient

Ni = 0.8; %Internal quantum efficiency

w = 2*pi*10e5;

Io = 10e-3;

%I = Io*sin(w*t);

I = 2.5*Io; %for test purposes

tp = 1/tau_p;

te = 1/tau_e;

Aint = 6; %Internal losses inside cavity waveguides

%G = ((a/Vp)* (N-(V*No)))/(1-eps*(Sc + Scc));

alpha = -2; %alpha factor

L = 76e-4 ;%size of the ring

wcb = 2*pi*70;

%R = 0.25;

Wcb = wcb*1000000;

%r = 1/R;

tpcw = Vg*(Aint + ((1/L)*log(4)));

Tpcw = 1/tpcw;

%------Rate equations-------

N = y(1);

Sc = y(2); %Clock wise photon number

yc = y(3);

Scc = y(4); %anti clockwise photon number

ycc = y(5);

G = ((a/Vp)* (N-(V*No)))/(1-eps*(Sc + Scc));

dydt(1) = (Ni*I)/q - y(1)*te - Vg*G*(y(2) + y(4)); %dN/dt

dydt(2) = (Vg*G-Tpcw)*y(2) + beta*y(1)*te; %dSc/dt

dydt(3) = -(alpha/2)*(Vg*G-Tpcw); %dyc/dt

dydt(4) = (Vg*G-Tpcw)*y(4) + beta*y(1)*te + ((2*Vg)/L)*cos(y(5))*(sqrt(Si*y(4))); %dScc/dt

dydt(5) = -Wcb - ((alpha/2)*(Vg*G-Tpcw)) - ((Vg/L)*sin(y(5))*(sqrt(Si/y(4)))); %dycc/dt

-----------This is the ode file-----------

%------Rate equations for requation file------

format bank;

close all;

clear all;

clc;

%time interval

ti=0; 

tf=200; 

tspan=[ti tf];

x0 = [3.75e7, 2.25e6, 0, 2.25e6, 0]; %initial vectors

%options= odeset('RelTol',100, 'AbsTol',[3.75e7, 2.25e6]);

[t,y]= ode23t(@requations,tspan,x0);

%Plotting the graphs:

figure 

subplot(5,1,1), plot(t,y(:,1),'r'),grid on; 

title('Laserrate equations'),ylabel('N'); 

subplot(5,1,2), plot(t,y(:,2),'b'),grid on; 

ylabel('Scw'); xlabel('t'); 

subplot(5,1,3), plot(t,y(:,3),'g'),grid on; 

ylabel('ycw');xlabel('t');

subplot(5,1,4), plot(t,y(:,3),'g'),grid on; 

ylabel('Sccw');xlabel('t');

subplot(5,1,5), plot(t,y(:,3),'g'),grid on; 

ylabel('yccw');xlabel('t');