Learning Forum

[amoghbs]

Hi,
I am trying to understand scattering loss in bend when transitioning from a straight waveguide mode to a bent one with specific waveguide dimensions, 2.4um in width and 80nm in depth and bend radius of 50um. I did the simulations in both FDFD and varFDTD but I am getting different transmission even though I think both are identical otherwise. I expected both the results to be different but the difference in T is too big. Could you please help me with this?

[Amrita Pati]

Hi Amogh,

Would you be able to share the screenshot of the geometry? I will recommend you to make sure that you are injecting the same mode (whether TE or TM) in both simulation. Have you tried performing any convergence testing, especially with respect to the mesh accuracy?

Regards,
Amrita

[amoghbs]

Hi Amrita,

Thanks for the reply. When you refer to convergence testing, you mean redoing the sims manually while changing the parameters till the value converges right? For FDTD, the Sims would take a very long time for each run

 

[Amrita Pati]

Hi Amogh,

Convergence testing can be done manually or using the sweeo utility. But you are correct, it is going to be time consuming. Would you be able to add an index monitor, something that would capture the bend in the plane it is in. The index monitor has a result called "index preview" for which you don't have to run the simulation. If you compare the two index previews (from FDTD and varFDTD), do you notice any differences?

Regards,
Amrita