www.pudn.com > FBG.zip > VI_matrix1.m, change:2009-07-15,size:661b


function S=VI_matrix1(Lambda,Lambda_D,N,Neff,d_Neff) 
%均匀光栅VI矩阵(快速) 
z=0.5*Lambda_D/2/Neff;          %平均每层厚度(总共N个周期=2*N层) 
phase=[2*pi*(Neff-d_Neff/2)/Lambda*z,2*pi*(Neff+d_Neff/2)/Lambda*z];   % 相位可选元素2*1 
Zj=[120*pi/(Neff-d_Neff/2),120*pi/(Neff+d_Neff/2)];                  % 阻抗可选元素2*1 
VI=[cos(phase(1)),j*Zj(1)*sin(phase(1));j*sin(phase(1))/Zj(1),cos(phase(1))]*[cos(phase(2)),j*Zj(2)*sin(phase(2));j*sin(phase(2))/Zj(2),cos(phase(2))]; 
VI0=VI; 
%**************最小重复单元VI 
n=2; 
while mod(N,n)==0 
    n=n*2; 
    VI=VI*VI; 
end 
%**************获取最大重复单元VI 
p=N/n*2; 
S=[1,0;0,1]; 
for n=1:p 
    S=S*VI; 
end