Amante Joshua Jr. Dumalus
We would like to ask how to get the amplitude coupling coefficients k's and t's. We are working to compare our ring resonator design with our analytical equation which is using the amplitude coupling coefficients as variables. We would like to make our analytically calculated transmission at through and drop ports to be very close to that of our simulation, which is why we need the amplitude coupling coefficients given a constant gap and coupling length from the simulation. If we are able to get the amplitude coupling cofficients and the corresponding transmission, we will then compare them with our analytical transmission with the same coupling coefficient and corresponding transmission. If they are the same, we are confident with our designs.
The matrix equation for instance in the Figure below, how do we get amplitude coupling coefficients? Are they always complex or is there a way to make them real?
 You mentioned something about S parameters, are they the amplitude coupling coefficients? May we also ask what source configurations should we use if we want amplitude coupling coefficients?
For example, do we need a broadband or narrowband source? Do we use one mode or multimode? We just want to get the amplitude coupling coefficient of a ring resonator design from Lumerical Mode.
Thank you very much!