www.pudn.com > FBG.zip > Cross.m, change:2009-05-22,size:862b


clear; 
np=442.857e-6;       %光栅周期% 
L=90*np        %光栅长度(m) 
n1=1.46;          %纤芯原始折射率% 
v=1;              %边缘可见度% 
DeltaN=1e-4;        %有效折射率微扰量(弱) 
D_Neff=0.0035;      %基模与包层模有效折射率差 
wl_D=D_Neff*np      %光栅设计波长参数 
 
 
wavelength=[1514:1:1674]*1e-9;      % 初始化输入波长区间 % 
wl_max=(1+DeltaN/D_Neff)*wl_D       % 最大耦合波长 
D_wl=wavelength./wl_max;            % 采样点间隔 
kLpi=DeltaN/wl_max*L                % k*L/pi 
delta=pi*D_Neff*(1/wl_max-1/wl_D)+pi*DeltaN/wl_max 
k=pi*v*DeltaN/wl_max 
 
for j=1:161 
   wl=(1514+j-1)*1e-9; 
   delta=pi*D_Neff*(1/wl-1/wl_D)+pi*DeltaN/wl; 
   k=pi*v*DeltaN/wl; 
   g=sqrt(delta^2+k^2); 
   CT(j)=(k^2/g^2)*sin(g*L)^2; 
end 
 
plot(D_wl,CT); 
axis([0.95 1.05 0 1]); 
title('耦合率'); 
xlabel('Normalized wavelength'); 
ylabel('Cross Transmission'); 
grid on;