计算脉冲在非线性耦合器中演化的Matlab 程序 *s/F4?*
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% This Matlab script file solves the coupled nonlinear Schrodinger equations of HH]LvK
% soliton in 2 cores coupler. The output pulse evolution plot is shown in Fig.1 of 1,/oS&?E
% Youfa Wang and Wenfeng Wang, “A simple and effective numerical method for nonlinear @U9ov >E
% pulse propagation in N-core optical couplers”, IEEE Photonics Technology lett. Vol.16, No.4, pp1077-1079, 2004 [[)HPHSQ
%@IR7v~
%fid=fopen('e21.dat','w'); +yYz ;, \
N = 128; % Number of Fourier modes (Time domain sampling points) l^SKd
M1 =3000; % Total number of space steps cL}g7D
J =100; % Steps between output of space s*Fmu7o43
T =10; % length of time windows:T*T0 rj6wKfz
T0=0.1; % input pulse width "{&!fD~w
MN1=0; % initial value for the space output location dtnAMa5$T
dt = T/N; % time step APF-*/K?
n = [-N/2:1:N/2-1]'; % Index -PX {W)Aw
t = n.*dt; ruA!+@or
u10=1.*sech(1*t); % input to waveguide1 amplitude: power=u10*u10 !W6]+
u20=u10.*0.0; % input to waveguide 2 >Rr]e`3wG
u1=u10; u2=u20; NTn-4iJy
U1 = u1; a~{mRh
U2 = u2; % Compute initial condition; save it in U e06r5%|.%
ww = 4*n.*n*pi*pi/T/T; % Square of frequency. Note i^2=-1. 8
/\rmf\
w=2*pi*n./T; rSa3u*xB
g=-i*ww./2; % w=2*pi*f*n./N, f=1/dt=N/T,so w=2*pi*n./T JU~l
L=4; % length of evoluation to compare with S. Trillo's paper :_vf1>[
dz=L/M1; % space step, make sure nonlinear<0.05 z7GLpTa
for m1 = 1:1:M1 % Start space evolution 7wZKK0;T
u1 = exp(dz*i*(abs(u1).*abs(u1))).*u1; % 1st sSolve nonlinear part of NLS z,^baU
u2 = exp(dz*i*(abs(u2).*abs(u2))).*u2;
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ca1 = fftshift(fft(u1)); % Take Fourier transform YUc&X