Reply To: EME Mode Sweep Not Converging

[Sept]

Hi Amrita,

that is correct, in the simulation the waveguides are lossless. If it helps at all I will attach my code along with a screenshot of my sweep (also for debuggin purposes I have seen that turning off csvs and energy conservation helped some of my paramaters conerge.

 

Code: 

 

selectall; deleteall; clear;

 

selectall; deleteall; clear;

 

if(materialexists("TFLN"))

 

{

 

deletematerial("TFLN");

 

}

 

 

####################Defining TFLN###########################

 

#Indices of refraction for substrate & waveguide layers

delta_n = 0;

n_TFLN = [2.21; 2.14; 2.21];

temp = addmaterial("Dielectric");

setmaterial(temp,"name","TFLN");

setmaterial("TFLN", "Anisotropy", 1); # enable diagonal anisotropy

setmaterial("TFLN","Refractive Index", n_TFLN);

 

 

########## SETTING UP VARIABLES THAT CAN BE PARAMETRIZED ##################

wg_taper_length=20e-6;

wg_height=0.3e-6;

slab_height=0.3e-6;

s_angle=pi/3;

add_length=wg_height/tan(s_angle);

wg_width=2.5e-6;

l=10.25e-6;

etch=550e-9;

 

##Setting Wg1

addrect;

set("x min",-3e-6);

set("x max",0);

set("y",0);

set("y span",wg_width);

set("z min",0);

set("z max",wg_height+slab_height);

set("name","Waveguide1");

set("material","TFLN");

 

##Setting Up Waveguide Middle

vtx=[0,0;0,wg_height+slab_height;wg_taper_length,wg_height+slab_height-etch;wg_taper_length,0];

addpoly;

set("vertices",vtx);

set("z",0);

set("z span",wg_width);

set("x",0);

set("y",0);

 set("first axis","x");

 set("rotation 1",90);

 set("name","Taper");

 set("material","TFLN");

 

###Setting Wg2

#addrect;

#set("x min",wg_taper_length);

#set("x max",wg_taper_length+3e-6);

#set("y",0);

#set("y span",wg_width);

#set("z min",0);

#set("z max",wg_height+slab_height-etch);

#set("name","Waveguide2");

#set("material","TFLN");

 

 

 

addmesh;

set("based on a structure",1);

set("structure","Taper");

set("buffer",0.1e-6);

set("dy",100e-9);

set("dz",1e-9);

 

#addmesh;

#set("based on a structure",1);

#set("structure","Waveguide2");

#set("buffer",0.1e-6);

#set("dy",50e-9);

#set("dz",1e-9);

 

addmesh;

set("based on a structure",1);

set("structure","Waveguide1");

set("buffer",0.1e-6);

set("dy",100e-9);

set("dz",1e-9);

 

 

 

yspan=6e-6;

zspan=6e-6;

 

addeme;

set("index",1.4440);

set("x min",-1e-6);

set("y min",-yspan);

set("y max",yspan);

set("z max",zspan);

set("z min",-zspan);

set("y min bc","metal");

set("y max bc","metal");

set("z min bc","metal");

set("z max bc","metal");

set("number of cell groups",2);

set("group spans",[1e-6;wg_taper_length]);

set("cells",[1;50]);

set("subcell method",[0; 0]);

set("energy conservation",1);

set("number of modes for all cell groups",60);

#set("allow custom eigensolver settings",1);

#set("modes",[20;60]);

set("wavelength",1.55e-6);

set("display cells",1);

set("mesh cells y",60);

set("mesh cells z",60);

#set("min mesh step",0.5e-9);

 

 

### Setting up Port 1 ###

select("EME::Ports::port_1");

set("use full simulation span",1);

set("mode selection","fundamental TE mode");

 

 

#### Setting up Port 2 ###

select("EME::Ports::port_2");

set("use full simulation span",1);

set("mode selection","fundamental TE mode");