Learning Forum

[minusunny]

Hi,

How can i calculate effective indices of first two modes of an subwavelength grating using FDTD ? Will using FDE work?

 

 

[Amrita Pati]

Hi,

You may use FDE, which is specfically developed to calculate the modes of a waveguide. Also, the mode source in FDTD has an inbuilt eignemode solver, which can also calculate the modes. But I would recommend FDE if you have the option.

Regards,
Amrita

[minusunny]

Will the result be accurate for SWG?

I am trying an example given in the following link:

How to calculate the effective index of bioperiodic SWG structures (ansys.com)

It only gives the effective index of first mode. I would like to get effective index with second mode in similar manner. Is there any possible way to do that? 

[Amrita Pati]

Hello,

Are you referring to the mode source used in a Bragg grating? By default the mode source only selects the fundamental mode.You can choose "user select", and then "select mode". This would open up the eigenmode solver and you should be able to calculate the modal properties of multiple modes.

Regards,
Amrita

[minusunny]

Hello,

I tried this. But when i try to plot. I am having different wavelength points for neff0 and neff1 while plotting may be because of using polyfit.If i remove polyfit i am not getting exact values for indices. Is there anyother way to calculate effective indices for SWGs?

I wanted to calculate beat length for MMI. 

Lpi = wavelength/2*(neff0-neff1).

Can i simulate SWG on EME?