clc
ti = 0;
tf = 1E-3;
tspan=[ti tf];
P = 1.27;
a = 0.1;
tc = 230E-6;
tp = 5.4E-9;
o = rand(1,5)*100E3;
k = 1E-3;
k1 = k;
k2 = k;
k3 = k;
k4 = k;
k5 = k;
f = @(t,y) [
(P - y(1).*((abs(y(6)))^2 +1))./tc;
(P - y(2).*((abs(y(7)))^2 +1))./tc;
(P - y(3).*((abs(y(8)))^2 +1))./tc;
(P - y(4).*((abs(y(9)))^2 +1))./tc;
(P - y(5).*((abs(y(10)))^2 +1))./tc;
(y(1)-a).*((y(6))./tp) + (k1./tp).*(y(7)).*cos(y(11)) + (k5./tp).*(y(10))*cos(y(15));
(y(2)-a).*((y(7))./tp) + (k2./tp).*(y(8)).*cos(y(12)) + (k1./tp).*(y(6))*cos(y(11));
(y(3)-a).*((y(8))./tp) + (k3./tp).*(y(9)).*cos(y(13)) + (k2./tp).*(y(7))*cos(y(12));
(y(4)-a).*((y(9))./tp) + (k4./tp).*(y(10)).*cos(y(14)) + (k3./tp).*(y(8))*cos(y(13));
(y(5)-a).*((y(10))./tp) + (k5./tp).*(y(9)).*cos(y(14)) + (k4./tp).* (y(6))*cos(y(15));
o(1,1) - (k1./tp).*(y(6)/y(7)).*(sin(y(11))) - (k1./tp).*(y(10)/y(6)).*(sin(y(11))) + (k2./tp).*(y(8)./y(7))*sin(y(12)) + (k5./tp).*(y(10)/y(6)).*sin(y(15));
o(1,2) - (k2./tp).*(y(7)/y(8)).*(sin(y(12))) - (k2./tp).*(y(8)/y(7)).*(sin(y(12))) + (k3./tp).*(y(9)./y(8))*sin(y(13)) + (k1./tp).*(y(6)/y(7)).*sin(y(11));
o(1,3) - (k3./tp).*(y(8)/y(9)).*(sin(y(13))) - (k3./tp).*(y(9)/y(8)).*(sin(y(13))) + (k4./tp).*(y(10)./y(9))*sin(y(14)) + (k2./tp).*(y(7)/y(8)).*sin(y(12));
o(1,4) - (k4./tp).*(y(9)/y(10)).*(sin(y(14))) - (k4./tp).*(y(10)/y(9)).*(sin(y(14))) + (k5./tp).*(y(6)./y(10))*sin(y(15)) + (k3./tp).*(y(8)/y(9)).*sin(y(13));
o(1,5) - (k5./tp).*(y(10)/y(6)).*(sin(y(15))) - (k5./tp).*(y(6)/y(10)).*(sin(y(15))) + (k1./tp).*(y(7)./y(6))*sin(y(11)) + (k4./tp).*(y(9)/y(10)).*sin(y(14));];
[time,Y] = ode45(f,tspan./tp,[0; 0; 0; 0; 0; 1; 1; 1; 1; 1; 0.01; 0.01; 0.01; 0.01; 0.01],o)
subplot 211
plot(time,Y(:,11));
xlabel('time')
ylabel('phase')
subplot 212
plot(time,Y(:,12));
xlabel('time')
ylabel('Amplitude')
Unfortunately your code is taking too much time to run.. I didnt check in details
But your Problem related to dimension is removed
