2danalyticalforpowerflow_1m.m

根据gloge能流公式编写的一个代码

D=7.5e-4;
%required from the paper "Ner mothod to calculate mode conversion
%coefficients in SI multimode optical fibers",2003
A=1.37;
%second order multiplicative factor in the series expansion of the power loss coefficient
b=4*(A*D)^0.5;
t=-30:0.05:30;
%the critical angle measure in air
z=1;% a coordinate along the fiber axis from the unput fiber end
s=t.*3.14/180;
% s is the propagation angle with respect to the core axis
s=(A/D)^0.5.*s.^2;
t0=25*3.14/180;
%the launched angle
x0=(A/D)^0.5*t0^2;
m=(4*x0.*x).^0.5*exp(-0.5*b*z)./(1-exp(-b*z));
I0=BESSELI(0,M);%the modified Bessel function of order zero
p=exp(-(x0+x).*(1+exp(-b*z))./(2.*(1-exp(-b*z)))).*(exp(-0.5*b*z)./(1-exp(-b*z))).*I0;
%assuming that the input power distribution is the Dirac delta function
%P(x,0)=delta(x-x0)
plot(t,p);