计算脉冲在非线性耦合器中演化的Matlab 程序 +t&)Z
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% This Matlab script file solves the coupled nonlinear Schrodinger equations of }aXS MxCd
% soliton in 2 cores coupler. The output pulse evolution plot is shown in Fig.1 of qxHn+O!h
% Youfa Wang and Wenfeng Wang, “A simple and effective numerical method for nonlinear jTV4iX
% pulse propagation in N-core optical couplers”, IEEE Photonics Technology lett. Vol.16, No.4, pp1077-1079, 2004 0c!^=(
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%fid=fopen('e21.dat','w'); 4^nHq 4_
N = 128; % Number of Fourier modes (Time domain sampling points) V6((5o#
M1 =3000; % Total number of space steps
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J =100; % Steps between output of space G973n
T =10; % length of time windows:T*T0 IuAu_`,Ndi
T0=0.1; % input pulse width )8}k.t>'s
MN1=0; % initial value for the space output location v''J@ F7
dt = T/N; % time step 8'TIDu
n = [-N/2:1:N/2-1]'; % Index dBovcc
t = n.*dt; `nEqw/I
u10=1.*sech(1*t); % input to waveguide1 amplitude: power=u10*u10 GVn'p
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u20=u10.*0.0; % input to waveguide 2 #8M^;4N>[
u1=u10; u2=u20; 8*{jxN'M
U1 = u1; gp $Rf9\
U2 = u2; % Compute initial condition; save it in U QkHG`yW
ww = 4*n.*n*pi*pi/T/T; % Square of frequency. Note i^2=-1. i1KjQ1\a +
w=2*pi*n./T; gae=+@z
g=-i*ww./2; % w=2*pi*f*n./N, f=1/dt=N/T,so w=2*pi*n./T h4hp5M
L=4; % length of evoluation to compare with S. Trillo's paper @]2aPs} }6
dz=L/M1; % space step, make sure nonlinear<0.05 ;/?w-)n?
for m1 = 1:1:M1 % Start space evolution F|.tn`j]U
u1 = exp(dz*i*(abs(u1).*abs(u1))).*u1; % 1st sSolve nonlinear part of NLS 2|B@s3a
u2 = exp(dz*i*(abs(u2).*abs(u2))).*u2; nec}grA
ca1 = fftshift(fft(u1)); % Take Fourier transform h?B1Emlq
ca2 = fftshift(fft(u2)); .v'`TD).6
c2=exp(g.*dz).*(ca2+i*1*ca1.*dz); % approximation 0CXXCa7!
c1=exp(g.*dz).*(ca1+i*1*ca2.*dz); % frequency domain phase shift ! os@G
u2 = ifft(fftshift(c2)); % Return to physical space X !0 7QKs
u1 = ifft(fftshift(c1)); 6o9&FU
if rem(m1,J) == 0 % Save output every J steps. Df *<3G
U1 = [U1 u1]; % put solutions in U array >py[g0J
U2=[U2 u2]; k2,`W2]^E
MN1=[MN1 m1]; ru`U/6n
z1=dz*MN1'; % output location VGxab;#,:3
end :~srl)|)
end whP5u/857
hg=abs(U1').*abs(U1'); % for data write to excel 9(z) ^G
ha=[z1 hg]; % for data write to excel .;ofRx<
t1=[0 t']; 2g?q4e,
hh=[t1' ha']; % for data write to excel file v.>K
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%dlmwrite('aa',hh,'\t'); % save data in the excel format |/%5~=%7
figure(1) \ )>#`X
waterfall(t',z1',abs(U1').*abs(U1')) % t' is 1xn, z' is 1xm, and U1' is mxn YN<vOv
figure(2) 5=<KA
waterfall(t',z1',abs(U2').*abs(U2')) % t' is 1xn, z' is 1xm, and U1' is mxn
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非线性超快脉冲耦合的数值方法的Matlab程序 }m5()@Q}a
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在研究脉冲在非线性耦合器中的演变时,我们需要求解非线性偏微分方程组。在如下的论文中,我们提出了一种简洁的数值方法。 这里我们提供给大家用Matlab编写的计算程序。 QUvSeNSp
Youfa Wang and Wenfeng Wang, “A simple and effective numerical method for nonlinear pulse propagation in N-core optical couplers”, IEEE Photonics Technology lett. Vol.16, No.4, pp1077-1079, 2004 PN<VqtW
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% This Matlab script file solves the nonlinear Schrodinger equations GXQ%lQ
% for 3 cores nonlinear coupler. The output plot is shown in Fig.2 of ZUS5z+o
% Youfa Wang and Wenfeng Wang, “A simple and effective numerical method for nonlinear `{
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% pulse propagation in N-core optical couplers”, IEEE Photonics Technology lett. Vol.16, No.4, pp1077-1079, 2004 d]^m^
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C=1; JZ5 ";*,
M1=120, % integer for amplitude .oTS7rYw
M3=5000; % integer for length of coupler xVX:kDX
N = 512; % Number of Fourier modes (Time domain sampling points) ~jHuJ`]DF
dz =3.14159/(sqrt(2.)*C)/M3; % length of coupler is divided into M3 segments, make sure nonlinearity<0.05. &y