| tianmen |
2011-06-12 18:33 |
求解光孤子或超短脈沖耦合方程的Matlab程序
計(jì)算脈沖在非線性耦合器中演化的Matlab 程序 6JYV C>i
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% This Matlab script file solves the coupled nonlinear Schrodinger equations of 28N
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% soliton in 2 cores coupler. The output pulse evolution plot is shown in Fig.1 of I8RPW:B; B
% Youfa Wang and Wenfeng Wang, “A simple and effective numerical method for nonlinear 5 u=(zg
% pulse propagation in N-core optical couplers”, IEEE Photonics Technology lett. Vol.16, No.4, pp1077-1079, 2004 ]*M-8_D
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%fid=fopen('e21.dat','w'); / y.+N`_
N = 128; % Number of Fourier modes (Time domain sampling points) cJ >
#jl&
M1 =3000; % Total number of space steps <,S5(pZ
J =100; % Steps between output of space ,( ?q
T =10; % length of time windows:T*T0 Q lmZ4fT[r
T0=0.1; % input pulse width t|ih{0
MN1=0; % initial value for the space output location |_7AN!7j
dt = T/N; % time step H ]X Y
n = [-N/2:1:N/2-1]'; % Index :"pA0oB
t = n.*dt; 9ne13 qVm+
u10=1.*sech(1*t); % input to waveguide1 amplitude: power=u10*u10 O
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u20=u10.*0.0; % input to waveguide 2 K Qz .g3,
u1=u10; u2=u20; {xGM_vH1
U1 = u1; X YM 5'
U2 = u2; % Compute initial condition; save it in U y]veqa
ww = 4*n.*n*pi*pi/T/T; % Square of frequency. Note i^2=-1. 0 F495'*A
w=2*pi*n./T; *C*'J7
g=-i*ww./2; % w=2*pi*f*n./N, f=1/dt=N/T,so w=2*pi*n./T yG`J3++
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L=4; % length of evoluation to compare with S. Trillo's paper Wt%+ q{
dz=L/M1; % space step, make sure nonlinear<0.05 kX2bU$1Q,i
for m1 = 1:1:M1 % Start space evolution aU)N bESu
u1 = exp(dz*i*(abs(u1).*abs(u1))).*u1; % 1st sSolve nonlinear part of NLS #Pf?.NrTn
u2 = exp(dz*i*(abs(u2).*abs(u2))).*u2; l|z0aF;z
ca1 = fftshift(fft(u1)); % Take Fourier transform #Oeb3U
ca2 = fftshift(fft(u2)); *x;&fyR
c2=exp(g.*dz).*(ca2+i*1*ca1.*dz); % approximation % rmn+L),;
c1=exp(g.*dz).*(ca1+i*1*ca2.*dz); % frequency domain phase shift )M!6y%b67
u2 = ifft(fftshift(c2)); % Return to physical space ^bZ'z
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