Learning Forum

[dinka.milovancev]

Hi, 

I am trying to simulate a taper between a rib waveguide and phase shifter modulator type waveguide in EME (current length of the taper is 10um):

This is the settup for mode and cells:

these are the boudary conditions:

My port are centered at the middle of the ridge:

In the EME setup I am using user defined dielectric as the background (1.44) and the structure is Si. I am also using mesh override region.

When I run the simulations the modes in the waveguide seem off:

and neff is 1.33

Could you advise on how to improve the simulation?

Best,

Dinka

 

 

 

[Amrita Pati]

Hi Dinka,

The mode profiles that you have showed, are they the fundamental mode at the input/output waveguides? 

What is the mesh resolution in the transverse direction?

Try increasing the size of the ports and see if that makes a difference in the effective index. Typically, we recommend the source span to be large enough to have the fields decayed sufficiently enough (close to 1e-05 of the peak) at the edges of the source.

You can select "user-select" in Mode selection in each port and then click on "Select Mode" to run the eignmode solver (just like an FDE simulation), this will give you more insights into the guided modes supported by the structure and then you can select the fundamental mode there.

Also try switching from "Metal" to "PML" for y-boundaries, does that make any difference?

Regards,
Amrita

[dinka.milovancev]

 

Dear Amrita,

I have fixed some mistakes such as the position in the z-axis of eme solver and also my simulation is not symmetric in z-direction. Now it looks ok.

Best,

Dinka

 

 

[dinka.milovancev]

 

 

 

 

 

 

[Amrita Pati]

Hi Dinka,

Thanks for letting me know.

Regards,
Amrita