silicon_channel.m

强大的计算电磁场本征函数与本征模的程序

% This example computes all of the field components of a
% silicon-on-insulator nanowire waveguide.

n1 = 1.46;          % SiO2 lower cladding
n2 = 3.50;          % Silicon core
n3 = 1.00;          % Air upper cladding

h1 = 500;           % lower cladding (nm)
h2 = 200;           % silicon core (nm)
h3 = 500;           % upper cladding (nm)

dx = 2.5;           % grid size (x)
dy = dx;            % grid size (y)

lambda = 1550;      % wavelength (nm)
nmodes = 1;         % number of modes to compute

w = 400;            % waveguide full-width (nm)
side = 500;         % space on side of waveguide (nm)

fprintf (1,'generating index mesh...\n');

[x,y,xc,yc,nx,ny,eps] = ...
    waveguidemesh([n1,n2,n3],[h1,h2,h3],h2,w/2,side,dx,dy);

% Now we stretch out the mesh at the boundaries:
[x,y,xc,yc,dx,dy] = stretchmesh(x,y,[200,200,200,0],[1.5,1.5,1.5,1]);

fprintf (1,'solving for eigenmodes...'); t = cputime;
[Hx,Hy,neff] = wgmodes (lambda, n2, nmodes, dx, dy, eps, '000A');
fprintf (1,'done (cputime = %7.3f)\n', cputime-t);

fprintf(1,'neff = %7.5f\n',neff);

fprintf (1,'post-processing...'); t = cputime;
[Hz,Ex,Ey,Ez] = postprocess (lambda, neff, Hx, Hy, dx, dy, eps, '000A');
fprintf (1,'done (cputime = %7.3f)\n', cputime-t);

ii = 1;
colormap(jet(256));
hn = max(abs(Hy(:)));
en = hn/n2;

subplot(231);
imagemode(x,y,Hx/hn,sprintf('Hx (mode %d)',ii));
hold on;
contourmode(x,y,Hx/hn,1,3,45,sprintf('Hx (mode %d)',ii));
hold off;
v = xlim();
line(v,[h1,h1]);
line([0,w/2,w/2],[h1+h2,h1+h2,h1]);

subplot(232);
imagemode(x,y,Hy/hn,sprintf('Hy (mode %d)',ii));
hold on;
contourmode(x,y,Hy/hn,1,3,45,sprintf('Hy (mode %d)',ii));
hold off;
v = xlim();
line(v,[h1,h1]);
line([0,w/2,w/2],[h1+h2,h1+h2,h1]);

subplot(233);
imagemode(x,y,Hz/hn,sprintf('Hz (mode %d)',ii));
hold on;
contourmode(x,y,Hz/hn,1,3,45,sprintf('Hz (mode %d)',ii));
hold off;
v = xlim();
line(v,[h1,h1]);
line([0,w/2,w/2],[h1+h2,h1+h2,h1]);

subplot(234);
imagemode(xc,yc,Ex/en,sprintf('Ex (mode %d)',ii));
hold on;
contourmode(xc,yc,Ex/en,1,3,60,sprintf('Ex (mode %d)',ii));
hold off;
v = xlim();
line(v,[h1,h1]);
line([0,w/2,w/2],[h1+h2,h1+h2,h1]);

subplot(235);
imagemode(xc,yc,Ey/en,sprintf('Ey (mode %d)',ii));
hold on;
contourmode(xc,yc,Ey/en,1,3,60,sprintf('Ey (mode %d)',ii));
hold off;
v = xlim();
line(v,[h1,h1]);
line([0,w/2,w/2],[h1+h2,h1+h2,h1]);

subplot(236);
imagemode(xc,yc,Ez/en,sprintf('Ez (mode %d)',ii));
hold on;
contourmode(xc,yc,Ez/en,1,3,60,sprintf('Ez (mode %d)',ii));
hold off;
v = xlim();
line(v,[h1,h1]);
line([0,w/2,w/2],[h1+h2,h1+h2,h1]);