uniform_fbg_temperaturechange.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

%% The following program is used to calculate the reflection spectrum of 
%  uniform FBG when the environmental temperature is changed.
%% First time:    2006-10-02 
hold on
T0=300;          % initial temperature
delta_T=60;      % temperature variation
T=T0+delta_T    
alpha=-1e-6;    % CFBG(Ge-doped,SiO2)temperature sensitivity coefficent
L=L*(1+alpha*delta_T);
Period=Period*(1+alpha*delta_T);
kesi=0;%8.9e-6;    % CFBG(Ge-doped,SiO2)thermo-optic coefficient 
Neff=Neff*(1+kesi*delta_T);
delta_N=delta_N*(1+kesi*delta_T);

for i=1:501
   k=pi*v*delta_N/lamda(i);
   Beita=2*pi*Neff/lamda(i);
   delta=2*pi*delta_N/lamda(i)+(Beita-pi/Period);
%  delta=2*pi*Neff*(1/lamda(i)-1/lamda_D)+2*pi/lamda(i)*delta_N;
   R(i)=(sinh((k^2-delta^2)^0.5*L))^2/((cosh((k^2-delta^2)^0.5*L))^2-delta^2/k^2);    % formula 22 from Erdogan Fiber Grating Spectra
end
plot(lamda,abs(R),'m');
axis([1.555e-6 1.563e-6 0 1]);