Learning Forum

[sicli21]

I want to calculate absorption caused by metal electrodes (Au, Al) near my waveguide (Si) ? Is it possible to calculate this in MODE or should I use FEEM ? Which boundary conditions are more suitable ? 

 

My question is very similar to /forum/forums/topic/propagation-loss-from-metal-electrodes/ 

But when I create a similar structure I don't get any guided mode

[Amrita Pati]

Hi,

You should be able to calculate the absorption using FDE. You will have to use PML BCs. It is a bit hard to guess why you are not seeing any modes without looking at the simulation file. It could be due to a number of reasons. 

1. Make sure that the wavelength is set correctly, note the unit of the wavelength in the solver.
2. Increase the number of trial modes.
3. If you have a rough idea of what the effective index of the mode will be, I will recommend you to look for modes near this index using the “search near n” option. For example, if you expect that the effective index of the mode will be around 2+1e-03i, then you can do the following:
   

We might also have to look into the BCs more carefully. But let’s start with the more straightforward steps first. Let me know if they do not work.

Regards,
Amrita

 

 

[sicli21]

Hi, thank you for your response. Both Increasing number of trial modes and searching near the refractive index of the structure where electrodes are disabled helped.