一个光波导的传输问题

GGHong

计算了一个光波导的传输问题。发现结果（参看附件中的图）无法接受，有高手知道怎么处理吗？谢谢。

参数：
2维光波导，宽0.5微米，长8微米，中心波长1.55微米，波导边界离背景边界距离0.5*10=5微米
波导折射率2.948，背景折射率1。

边界条件：
波导的入口和出口设置为"端口" (port)，其他边界为"完美电导体" (perfect electric conductor)

网格划分：
先设置最大网格尺寸为1.55/10=0.155微米，然后再使用自动"细划网格"一次。

在Comsol中完成后，存为的.m文件如下：


% COMSOL Multiphysics Model M-file
% Generated by COMSOL 3.5 (COMSOL 3.5.0.494, $Date: 2008/09/19 16:09:48 $)

flclear fem

% COMSOL version
clear vrsn
vrsn.name = 'COMSOL 3.5';
vrsn.ext = '';
vrsn.major = 0;
vrsn.build = 494;
vrsn.rcs = '$Name:  $';
vrsn.date = '$Date: 2008/09/19 16:09:48 $';
fem.version = vrsn;

% Constants
fem.const = {'l','8e-6', ...
  'w','0.5e-6', ...
  'del','w*10', ...
  'nsi','2.948', ...
  'nair','1', ...
  'lambdac','1.55e-6'};

% Geometry
g1=rect2('w','l','base','corner','pos',{'-w/2','0'},'rot','0','const',fem.const);
g2=rect2('w+del*2','l','base','corner','pos',{'-w/2-del','0'},'rot','0','const',fem.const);

% Analyzed geometry
clear s
s.objs={g1,g2};
s.name={'R1','R2'};
s.tags={'g1','g2'};

fem.draw=struct('s',s);
fem.geom=geomcsg(fem);

% Initialize mesh
fem.mesh=meshinit(fem, ...
                  'hmax',[1.55e-6/10]);

% Refine mesh
fem.mesh=meshrefine(fem, ...
                    'mcase',0, ...
                    'rmethod','regular');

% (Default values are not included)

% Application mode 1
clear appl
appl.mode.class = 'InPlaneWaves';
appl.name = 'rfweh';
appl.module = 'RF';
appl.gporder = 4;
appl.cporder = 2;
appl.sshape = 2;
appl.assignsuffix = '_rfweh';
clear prop
prop.field='TETM';
prop.inputvar='lambda';
appl.prop = prop;
clear bnd
bnd.inport = {0,0,1,0};
bnd.type = {'E0','cont','port','port'};
bnd.modespec = {'userdef','userdef','analytic','analytic'};
bnd.portnr = {1,1,1,2};
bnd.ind = [1,1,1,2,3,4,2,1,1,1];
appl.bnd = bnd;
clear equ
equ.n = {'nair','nsi'};
equ.matparams = 'n';
equ.ind = [1,2,1];
appl.equ = equ;
appl.var = {'lambda0','1.55e-6'};
fem.appl{1} = appl;
fem.frame = {'ref'};
fem.border = 1;
clear units;
units.basesystem = 'SI';
fem.units = units;

% ODE Settings
clear ode
clear units;
units.basesystem = 'SI';
ode.units = units;
fem.ode=ode;

% Multiphysics
fem=multiphysics(fem);

% Extend mesh
fem.xmesh=meshextend(fem);

% Solve problem
fem.sol=femstatic(fem, ...
                  'complexfun','on', ...
                  'solcomp',{'Hz','Ez'}, ...
                  'outcomp',{'Hz','Ez'}, ...
                  'blocksize','auto');

% Save current fem structure for restart purposes
fem0=fem;

% Plot solution
postplot(fem, ...
         'tridata',{'Ez','cont','internal','unit','V/m'}, ...
         'trimap','jet(1024)', ...
         'title','Surface: Electric field, z component [V/m]', ...
         'axis',[-8.429981697180693E-6,8.429981697180693E-6,-3.999999989900971E-7,8.399999978792039E-6]);


[ 本帖最后由 GGHong 于 2009-2-3 05:53 编辑 ]