计算脉冲在非线性耦合器中演化的Matlab 程序 MOG[cp b~b(Ed{r % This Matlab script file solves the coupled nonlinear Schrodinger equations of
zHB{I(q % soliton in 2 cores coupler. The output pulse evolution plot is shown in Fig.1 of
t{>66jm\R % Youfa Wang and Wenfeng Wang, “A simple and effective numerical method for nonlinear
8 8U4I % pulse propagation in N-core optical couplers”, IEEE Photonics Technology lett. Vol.16, No.4, pp1077-1079, 2004
N) h>Ie XI\aZ\v %fid=fopen('e21.dat','w');
7Yxy2[ N = 128; % Number of Fourier modes (Time domain sampling points)
G6eC.vU]j M1 =3000; % Total number of space steps
Ik1,?A J =100; % Steps between output of space
4T9hT~cT7 T =10; % length of time windows:T*T0
ZZE T0=0.1; % input pulse width
fu=}E5ScK MN1=0; % initial value for the space output location
&u"*vG (U[ dt = T/N; % time step
`z)!!y n = [-N/2:1:N/2-1]'; % Index
im+2)9f t = n.*dt;
M Zw%s(lv u10=1.*sech(1*t); % input to waveguide1 amplitude: power=u10*u10
{7eKv+30 u20=u10.*0.0; % input to waveguide 2
@\!wW-:A u1=u10; u2=u20;
q 'hV ' U U1 = u1;
^^?DYC
U2 = u2; % Compute initial condition; save it in U
;^DU tr
; ww = 4*n.*n*pi*pi/T/T; % Square of frequency. Note i^2=-1.
!nj%n w=2*pi*n./T;
dY\"'LtF g=-i*ww./2; % w=2*pi*f*n./N, f=1/dt=N/T,so w=2*pi*n./T
:/vB,JC L=4; % length of evoluation to compare with S. Trillo's paper
9v
cUo?/ dz=L/M1; % space step, make sure nonlinear<0.05
.3|9 ~] for m1 = 1:1:M1 % Start space evolution
Ti3BlWQH u1 = exp(dz*i*(abs(u1).*abs(u1))).*u1; % 1st sSolve nonlinear part of NLS
#4//2N u2 = exp(dz*i*(abs(u2).*abs(u2))).*u2;
A ]U] ca1 = fftshift(fft(u1)); % Take Fourier transform
MmWJYF= ca2 = fftshift(fft(u2));
BQS9q 'u_ c2=exp(g.*dz).*(ca2+i*1*ca1.*dz); % approximation
4!k={Pd c1=exp(g.*dz).*(ca1+i*1*ca2.*dz); % frequency domain phase shift
t 48(GKF u2 = ifft(fftshift(c2)); % Return to physical space
$xu ?zd" u1 = ifft(fftshift(c1));
y-n\;d>[( if rem(m1,J) == 0 % Save output every J steps.
-'PpY302 U1 = [U1 u1]; % put solutions in U array
`FJnR~d
U2=[U2 u2];
Xq>e]#gR MN1=[MN1 m1];
;7`<.y z1=dz*MN1'; % output location
ri JyH;) end
_f3A6ER` end
zW0AB8l hg=abs(U1').*abs(U1'); % for data write to excel
){YPP !8cI ha=[z1 hg]; % for data write to excel
M?cKt.t t1=[0 t'];
Y6L+3*Qt hh=[t1' ha']; % for data write to excel file
uAj GR %dlmwrite('aa',hh,'\t'); % save data in the excel format
BRD'5 1]| figure(1)
[ V)sCAW waterfall(t',z1',abs(U1').*abs(U1')) % t' is 1xn, z' is 1xm, and U1' is mxn
"j a0,%3 figure(2)
~M'\9 waterfall(t',z1',abs(U2').*abs(U2')) % t' is 1xn, z' is 1xm, and U1' is mxn
P/I{q s .@6]_h; 非线性超快脉冲耦合的数值方法的Matlab程序 gs8L/veP <go~WpA|r 在研究脉冲在非线性耦合器中的演变时，我们需要求解非线性偏微分方程组。在如下的
论文中，我们提出了一种简洁的数值方法。 这里我们提供给大家用Matlab编写的计算程序。
T![K
i Youfa Wang and Wenfeng Wang, “A simple and effective numerical method for nonlinear pulse propagation in N-core optical couplers”, IEEE Photonics Technology lett. Vol.16, No.4, pp1077-1079, 2004
99ha /t 7l VIN&.= rp'fli? 0e d(@A % This Matlab script file solves the nonlinear Schrodinger equations
b(SV_.4,' % for 3 cores nonlinear coupler. The output plot is shown in Fig.2 of
b<F 4_WF % Youfa Wang and Wenfeng Wang, “A simple and effective numerical method for nonlinear
VNYLps@4H % pulse propagation in N-core optical couplers”, IEEE Photonics Technology lett. Vol.16, No.4, pp1077-1079, 2004
4*+ EUJ| ,g,jY]o C=1;
9iF e^^<ss M1=120, % integer for amplitude
p_z"Uwp M3=5000; % integer for length of coupler
-ufmpq. N = 512; % Number of Fourier modes (Time domain sampling points)
<{ ) 4gvH dz =3.14159/(sqrt(2.)*C)/M3; % length of coupler is divided into M3 segments, make sure nonlinearity<0.05.
Mb>6 .l T =40; % length of time:T*T0.
uf;q/Wr dt = T/N; % time step
* 2AQ'%U~ n = [-N/2:1:N/2-1]'; % Index
)2FO+_K? T t = n.*dt;
Dz50,*}J ww = 4*n.*n*pi*pi/T/T; % Square of frequency. Note i^2=-1.
gNqV>p w=2*pi*n./T;
z JnVO$A' g1=-i*ww./2;
Un/fP1 g2=-i*ww./2; % w=2*pi*f*n./N, f=1/dt=N/T,so w=2*pi*n./TP=0;
0&.lSwa g3=-i*ww./2;
I)Lb"
P1=0;
wi9| P2=0;
'QS"4EvdD P3=1;
?
w?k-v P=0;
!X8UP{J)L for m1=1:M1
m@,>d_|-K- p=0.032*m1; %input amplitude
r{Q< a s10=p.*sech(p.*t); %input soliton pulse in waveguide 1
zOE6;c8 1 s1=s10;
pMquu&Td s20=0.*s10; %input in waveguide 2
yhdG 93 s30=0.*s10; %input in waveguide 3
>1~`tP s2=s20;
h]Oplp4 \W s3=s30;
5qr!OEF2 p10=dt*(sum(abs(s10').*abs(s10'))-0.5*(abs(s10(N,1)*s10(N,1))+abs(s10(1,1)*s10(1,1))));
hX_p5a1t %energy in waveguide 1
{@#L'i| p20=dt*(sum(abs(s20').*abs(s20'))-0.5*(abs(s20(N,1)*s20(N,1))+abs(s20(1,1)*s20(1,1))));
84!4Vz^ %energy in waveguide 2
=_dd4`G&< p30=dt*(sum(abs(s30').*abs(s30'))-0.5*(abs(s30(N,1)*s30(N,1))+abs(s30(1,1)*s30(1,1))));
vQ/\BN %energy in waveguide 3
^ <VE5OM for m3 = 1:1:M3 % Start space evolution
JKT+ q*V s1 = exp(dz*i*(abs(s1).*abs(s1))).*s1; % 1st step, Solve nonlinear part of NLS
DXz8C - s2 = exp(dz*i*(abs(s2).*abs(s2))).*s2;
spx;QLo s3 = exp(dz*i*(abs(s3).*abs(s3))).*s3;
(RmED\.]4 sca1 = fftshift(fft(s1)); % Take Fourier transform
.V3Dql@z" sca2 = fftshift(fft(s2));
+r $.v|6 sca3 = fftshift(fft(s3));
3b 3cNYP sc1=exp(g1.*dz).*(sca1+i*C*sca2.*dz); % 2nd step, frequency domain phase shift
Mak9qaWqF> sc2=exp(g2.*dz).*(sca2+i*C*(sca1+sca3).*dz);
9-Qtj49 sc3=exp(g3.*dz).*(sca3+i*C*sca2.*dz);
u-9t s s3 = ifft(fftshift(sc3));
+2}(]J=- s2 = ifft(fftshift(sc2)); % Return to physical space
M0zD)@ s1 = ifft(fftshift(sc1));
(d;(FBk=' end
8 -5 jr_* p1=dt*(sum(abs(s1').*abs(s1'))-0.5*(abs(s1(N,1)*s1(N,1))+abs(s1(1,1)*s1(1,1))));
#Q@6:bBzv p2=dt*(sum(abs(s2').*abs(s2'))-0.5*(abs(s2(N,1)*s2(N,1))+abs(s2(1,1)*s2(1,1))));
a1`cI5n p3=dt*(sum(abs(s3').*abs(s3'))-0.5*(abs(s3(N,1)*s3(N,1))+abs(s3(1,1)*s3(1,1))));
DP_Pqn8p&M P1=[P1 p1/p10];
62x< rph P2=[P2 p2/p10];
3K!0 4\ P3=[P3 p3/p10];
'Xl>,\'6 P=[P p*p];
&{/>Sv!6# end
H27Oq8 figure(1)
OZ;E&IL plot(P,P1, P,P2, P,P3);
Zax] i,Bx =+h!JgY/L 转自：
http://blog.163.com/opto_wang/
