计算脉冲在非线性耦合器中演化的Matlab 程序 f3\w99\o
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% This Matlab script file solves the coupled nonlinear Schrodinger equations of q
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% soliton in 2 cores coupler. The output pulse evolution plot is shown in Fig.1 of 6l=M;B7:i
% Youfa Wang and Wenfeng Wang, “A simple and effective numerical method for nonlinear OHQ3+WJ
% pulse propagation in N-core optical couplers”, IEEE Photonics Technology lett. Vol.16, No.4, pp1077-1079, 2004 )8\Z=uC
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%fid=fopen('e21.dat','w'); jeyaT^F(
N = 128; % Number of Fourier modes (Time domain sampling points) Z|f^nH#-C
M1 =3000; % Total number of space steps !/[AQ{**T!
J =100; % Steps between output of space g9! dpP
T =10; % length of time windows:T*T0 pvI&-D #}
T0=0.1; % input pulse width w 2s,
MN1=0; % initial value for the space output location "F04c|oR<X
dt = T/N; % time step 9n-RXVL+
n = [-N/2:1:N/2-1]'; % Index fdvi}SS8
t = n.*dt; ]q@rGD85K
u10=1.*sech(1*t); % input to waveguide1 amplitude: power=u10*u10 `z5v}T
u20=u10.*0.0; % input to waveguide 2 X/K| WOO6
u1=u10; u2=u20; 9?v)
U1 = u1; I*%&)Hj~
U2 = u2; % Compute initial condition; save it in U oM m/!Dc
ww = 4*n.*n*pi*pi/T/T; % Square of frequency. Note i^2=-1. 6eVe}V4W
w=2*pi*n./T; &fh.w]\
g=-i*ww./2; % w=2*pi*f*n./N, f=1/dt=N/T,so w=2*pi*n./T +*]SP@|IYI
L=4; % length of evoluation to compare with S. Trillo's paper g=)U_DPRi
dz=L/M1; % space step, make sure nonlinear<0.05 )GQD*b
for m1 = 1:1:M1 % Start space evolution e=|F(iW
u1 = exp(dz*i*(abs(u1).*abs(u1))).*u1; % 1st sSolve nonlinear part of NLS )yfOrsM
u2 = exp(dz*i*(abs(u2).*abs(u2))).*u2; `=WzG"
ca1 = fftshift(fft(u1)); % Take Fourier transform mvxc[
ca2 = fftshift(fft(u2)); L+`}euu5
c2=exp(g.*dz).*(ca2+i*1*ca1.*dz); % approximation }d$vcEI$3
c1=exp(g.*dz).*(ca1+i*1*ca2.*dz); % frequency domain phase shift Zm?G'06
u2 = ifft(fftshift(c2)); % Return to physical space C _k_D
u1 = ifft(fftshift(c1)); \v B9fA:*
if rem(m1,J) == 0 % Save output every J steps. !!\4'Q[
U1 = [U1 u1]; % put solutions in U array m|g$'vjk
U2=[U2 u2]; 1mkQ"E4
MN1=[MN1 m1]; GN8`xR{J*
z1=dz*MN1'; % output location h=mI{w*
end E9
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end y$"~^8"z
hg=abs(U1').*abs(U1'); % for data write to excel 9.]Cy8
ha=[z1 hg]; % for data write to excel ?3e!A9x
t1=[0 t']; cJ1{2R
hh=[t1' ha']; % for data write to excel file \ltE rd-
%dlmwrite('aa',hh,'\t'); % save data in the excel format Qt)7mf
figure(1) X,Q6
waterfall(t',z1',abs(U1').*abs(U1')) % t' is 1xn, z' is 1xm, and U1' is mxn bDcWb2lqs
figure(2) S@l
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waterfall(t',z1',abs(U2').*abs(U2')) % t' is 1xn, z' is 1xm, and U1' is mxn f^>lObvd
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非线性超快脉冲耦合的数值方法的Matlab程序 '{1W)X
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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。 mDe+ M{/
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 Yn?2,^?N
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% This Matlab script file solves the nonlinear Schrodinger equations U(=f5|-
% for 3 cores nonlinear coupler. The output plot is shown in Fig.2 of rA>R`
% Youfa Wang and Wenfeng Wang, “A simple and effective numerical method for nonlinear 0*'`%W+5
% pulse propagation in N-core optical couplers”, IEEE Photonics Technology lett. Vol.16, No.4, pp1077-1079, 2004 p3'mJ3MA
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