test.m

利用传输矩阵法计算光纤啁啾brag光纤光栅滤波器的温度滤波特性

hold on
count=0;
for i=1:M  % using transmit matrix method to obtain the reflecting spectrum                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            
       F=[1,0;0,1];                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               
   for k=1:M                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         
% 	      Period(k)=Period(k)*(1+alpha*delta_T);
%         Beita(k)=Beita(k)*(1+kesi*delta_T);
        if k<2
           sigma=(Beita(i,k)-pi/Period(k))+2*pi*delta_N(k)/lamda(i); %(formula 17 from Erdogan's 'Fiber Grating Spectra' )
        else
           sigma=(Beita(i,k)-pi/Period(k))+2*pi*delta_N(k)/lamda(i)+8*pi*Neff^2*(l/2)/lamda(k)^2*(Period(k)-Period(k-1))/l;   
        end
        K=pi*v(k)*delta_N(k)/lamda(i);
        sub=sqrt(K^2-sigma^2);       
        F=F*[cosh(sub*L/M)-j*(sigma/sub)*sinh(sub*L/M),-j*(K/sub)*sinh(sub*L/M);j*(K/sub)*sinh(sub*L/M),cosh(sub*L/M)+j*(sigma/sub)*sinh(sub*L/M)];  %传输矩阵
        count=count+1
    end                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     
        r_design(i)=(abs(F(3)/F(1)))^2;                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  
end                                                                                                                                                                                                                                                                                                                                                                                                                                           
       plot(lamda,r_design,'r');