Learning Forum

[rezoana.arif]

Hi everyone,

I am trying to simulate a gaussian source vertically faced on top of the surface of CBG. The distance from between the source and the surface is 2 um. I am not sure whether this distance is good enough to have coupling. Is there any specific distance that I should maintain to have a good coupling between the optical source and the Circular Bragg grating?
I will appriciate any suggestion.

[Amrita Pati]

Hi Rezoana,

It seems to me more like a theoretical issue. I believe it will depend upon your geometry and the specific light-matter interactions that will take place. You can run a simulation for different distances and see how the coupling efficiency changes. Or maybe you could also try setting up an optimization task with the distance as a parameter within a specific range and the coupling efficiency as the objective function to determine what would be the best distance.

Regards,
Amrita

[rezoana.arif]

Hi Amrita,

Thank you for your reply. I found this video to calculate the power coupling in Mode solver. Is there any direct way to calculate the power coupling in FDTD solver?

Best Regards,

Rezoana

[Amrita Pati]

Hi Rezoana,

You can use frequency domain monitors (Frequncy Domain Field and Power) in FDTD to calculate the coupling efficiency. I will recommend you to look at this Grating Coupler example: Grating Coupler. This is a similar use case and might give you insights on how to setup your own simulation.You can also run the attached simulation files yourself. Here, the coupling efficieny is optimized for different paramters.

Regards,
Amrita

[rezoana.arif]

Hi Amrita,

Hi Amrita,

Thanks a bunch.
Best Regards,

Rezoana