一、创建结构
switchtolayout;
selectall;
delete;## SIM PARAMS
num_wg = 4;
wg_width = 0.5e-6;
out_wg_dist = 1e-6;
mode_width = 3*wg_width;
total_wg_h = num_wg*wg_width + (num_wg-1)*out_wg_dist;opt_size_x=6e-6;
opt_size_y=6e-6;size_x=opt_size_x+1e-6;
size_y=opt_size_y+1e-6;wg_index = 2.8;
bg_index = 1.44;dx = 20e-9;addrect;
set('name','input wg');
set('x min',-size_x);
set('x max',-opt_size_x/2 + 5e-7);
set('y',0);
set('y span',wg_width);
set('z span',220e-9);
set('index',wg_index);for( i=1:num_wg ) {addrect;set('name','output wg '+num2str(i));set('x min',opt_size_x/2 - 5e-7);set('x max',size_x);set('y',-total_wg_h/2 + (wg_width/2) + (i-1)*(out_wg_dist+wg_width));set('y span',wg_width);set('z span',220e-9);set('index',wg_index);
}addmode;
set('direction','Forward');
set('injection axis','x-axis');
set('y',0);
set('y span',mode_width);
set('x',-size_x/2+0.2e-6);
set('center wavelength',1550e-9);
set('wavelength span',0);
set('mode selection','fundamental TE mode');addfdtd;
set('dimension','2D');
set('index',bg_index);
set('mesh accuracy',3);
set('x min',-size_x/2);
set('x max',size_x/2);
set('y min',-size_y/2);
set('y max',size_y/2);
set('auto shutoff min',1e-6);
set('simulation time',5000e-15);addpower;
set('name','opt_fields');
set('monitor type','2D Z-normal');
set('x',0);
set('x span',opt_size_x);
set('y min',-opt_size_y/2);
set('y max',opt_size_y/2);for( i=1:num_wg ) { addpower;set('name','fom_'+num2str(i));set('monitor type','2D X-normal');set('x', size_x/2-0.2e-6);set('y',-total_wg_h/2 + (wg_width/2) + (i-1)*(out_wg_dist+wg_width));set('y span',mode_width);addmesh;set('name','fom_'+num2str(i)+'_mesh');set('override x mesh',true);set('dx',dx);set('override y mesh',false);set('override z mesh',false);set('x', size_x/2-0.2e-6);set('x span',2*dx);set('y',-total_wg_h/2 + (wg_width/2) + (i-1)*(out_wg_dist+wg_width));set('y span',mode_width);
} ## Global index monitor for visualization (export to VTK)
addindex;
set('name','global_index');
set('x min',-size_x/2);
set('x max',size_x/2);
set('y min',-size_y/2);
set('y max',size_y/2);## Optional: Naive design which can be used as initial guess
addstructuregroup;
set("name","initial_guess");
for( i=1:num_wg ) {
addwaveguide;
set("name","bend"+num2str(i));
set("base width",500e-9);
set("base height",240e-9);
set("base angle",90);
poles = [-opt_size_x/2,0;0,0;0,-total_wg_h/2 + (wg_width/2) + (i-1)*(out_wg_dist+wg_width);opt_size_x/2,-total_wg_h/2 + (wg_width/2) + (i-1)*(out_wg_dist+wg_width)];
set("poles",poles);
set("index",wg_index);
addtogroup("initial_guess");
}
二、 优化算法
######## IMPORTS ########
# General purpose imports
import os
import sys
import numpy as np# Optimization specific imports
from lumopt import CONFIG
from lumopt.ge
