Reply To: Ring Resonator mode source issue

[Amrita Pati]

Hi Fakhriyya,

As you might know, what varFDTD does is take the vertical permittivity/index profile at a certain location, and then calculates an effective mode. And then propagates this mode in 2D to simulate the overall device. The effective mode calculation is done either under a TE framework or a TM framework. This is chosen from the Effective Index Tab of the varFDTD solver object. For example, in this case I recommended you to use the H mode (TM) because the fundamental mode is a TM mode (You can tell from the polarization fraction). In order for the varFDTD simulation to be accurate, we have to make sure that the mode we use a TE mode as a source, then the effective mode calculation should also be done under TE, and same goes on for the TM mode. 

I am not sure why the device doesn't show the usual transmission dips for the TM mode, it could just be that the device was optimized for a TE mode. My understanding is that it is a very old example and it will be hard to track down who worked on this. Are you eventually planning to simulate some of your own ring modulators using varFDTD?

Regards,
Amrita