Devika Padmakumar Nair
Ansys Employee



DFT monitor records data for specified wavelength. The data is a mixture of all modes that were excited during the propagation. So the monitor might not be a good way to get the result.

I would suggest to usemode source and mode expansion monitor to get mode profile and S parameter or a or b coefficient to calculate mode amplitude.

Note 1 : If there is propagation and waveguide changes, the field profile is not a single mode. mode expansion monitor or port should be used to decompose the monitor data 

Note 2: FDE also produce nomalized results if cross section of waveguide is uniform. But in your simulation its not the case.

Hope this helps.