计算脉冲在非线性耦合器中演化的Matlab 程序 `FwE^_9d
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% This Matlab script file solves the coupled nonlinear Schrodinger equations of Bus]OF>hu
% soliton in 2 cores coupler. The output pulse evolution plot is shown in Fig.1 of :!^NjO
% Youfa Wang and Wenfeng Wang, “A simple and effective numerical method for nonlinear 0\Tp/Ph
% pulse propagation in N-core optical couplers”, IEEE Photonics Technology lett. Vol.16, No.4, pp1077-1079, 2004 aQ-SrxmO8
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%fid=fopen('e21.dat','w'); <7! "8e
N = 128; % Number of Fourier modes (Time domain sampling points) J50n
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M1 =3000; % Total number of space steps S f6%A
J =100; % Steps between output of space eVd:C8q
T =10; % length of time windows:T*T0 bVzJOBe
T0=0.1; % input pulse width NKc<nYdK?
MN1=0; % initial value for the space output location T\#Gc4
dt = T/N; % time step /|3~LvIt=
n = [-N/2:1:N/2-1]'; % Index (b.4&P"0
t = n.*dt; J #5V>7G
u10=1.*sech(1*t); % input to waveguide1 amplitude: power=u10*u10 ~NB|BwAh
u20=u10.*0.0; % input to waveguide 2 x.$cP
u1=u10; u2=u20; qMoo#UX
U1 = u1; {-Gh 62hDg
U2 = u2; % Compute initial condition; save it in U _ gGA/
ww = 4*n.*n*pi*pi/T/T; % Square of frequency. Note i^2=-1. hAt4+O&P
w=2*pi*n./T; ' 6)Yf}I
g=-i*ww./2; % w=2*pi*f*n./N, f=1/dt=N/T,so w=2*pi*n./T my/KsB
L=4; % length of evoluation to compare with S. Trillo's paper i'.D=o
dz=L/M1; % space step, make sure nonlinear<0.05 yo8mfH_,
for m1 = 1:1:M1 % Start space evolution 9GsG* $-I
u1 = exp(dz*i*(abs(u1).*abs(u1))).*u1; % 1st sSolve nonlinear part of NLS >I-rsw2
u2 = exp(dz*i*(abs(u2).*abs(u2))).*u2; <Mu T7x-
ca1 = fftshift(fft(u1)); % Take Fourier transform KyQTrl.qdl
ca2 = fftshift(fft(u2)); fg lN_
c2=exp(g.*dz).*(ca2+i*1*ca1.*dz); % approximation *3]2vq
c1=exp(g.*dz).*(ca1+i*1*ca2.*dz); % frequency domain phase shift e1y#p3 @d
u2 = ifft(fftshift(c2)); % Return to physical space |~#A?mK-
u1 = ifft(fftshift(c1)); l *{Bz5hc
if rem(m1,J) == 0 % Save output every J steps. X,Rl&K\b"
U1 = [U1 u1]; % put solutions in U array C/QrkTi=
U2=[U2 u2]; MPK rr
MN1=[MN1 m1]; It<VjN9
z1=dz*MN1'; % output location \RtFF
end ^IyYck'y+
end w~:F?
hg=abs(U1').*abs(U1'); % for data write to excel a5aHv/W#P
ha=[z1 hg]; % for data write to excel +SE \c
t1=[0 t']; =qbN?a/?2
hh=[t1' ha']; % for data write to excel file L8H:,} 2
%dlmwrite('aa',hh,'\t'); % save data in the excel format FS=LpvOG)
figure(1) n).*=YLN
waterfall(t',z1',abs(U1').*abs(U1')) % t' is 1xn, z' is 1xm, and U1' is mxn IuA4eDr^Y%
figure(2) ~d3@x\I?
waterfall(t',z1',abs(U2').*abs(U2')) % t' is 1xn, z' is 1xm, and U1' is mxn LwTdmR
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非线性超快脉冲耦合的数值方法的Matlab程序 $|7=$~y
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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。 m9\"B3sr
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 cr|]\
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% This Matlab script file solves the nonlinear Schrodinger equations gs7_Q
% for 3 cores nonlinear coupler. The output plot is shown in Fig.2 of j8
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% Youfa Wang and Wenfeng Wang, “A simple and effective numerical method for nonlinear CrSBN~
% pulse propagation in N-core optical couplers”, IEEE Photonics Technology lett. Vol.16, No.4, pp1077-1079, 2004 Kv9FqrDj
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