Im using VarFDTD in MODE solutions to simulate relative large (R=15-30 microns at 500nm ) ring resonators in polymer n=1.57. Im doing some variation in the radius varying it from 15 microns to 25 and studying the transmittance (only one port) and im also doing it for different gaps.
Imagine that I star running my simulations with a fixed gap 400 for 3 different radius R=15 R=20 and R=25. For the first one the peak doesn’t drop to zero and we are overcoupled. If we increase the radius R=20 I obtain even less transmitance (more coupling length-stronger coupling) so we are even more over coupled. This trend is normal when i increase the radius (R=16,17,18,19 ) each radius, but when i arrive around R=24-25 breaks this trend and thetransmission peak drops aproximating to zero. For my point of view I would still expect a more overcoupled resonator (since we are increasing the couplign region increasing the radius). I sincerely do not know what it is happening. I have already try to improve simulation time but it did not get what i expect (i do not get anoying ripples or something).
I do not know if it is better to do it in IC i do not have a lot of time to train myself in new softwares.
LEt me know if someone need printscreen or something.