I started by designing the structure (ring resonator with single bus waveguide) in FDTD.
Dimmensions: Radius 10 um, waveguide width 450 nm, gap ring-waveguide 700 nm, silicon height 220 nm.
I then, extracted the results from the 4 monitors to Matlab, got a file to import in Interconnect and got the ring through and drop port transmission. For TE mode looks fine.
When I simulate with the TM mode i get something like this. It looks like the response is not passive anymore. Even the reciprocity between through and drop response is small.
Some parameters I have in the FDTD design: frequency points 1001, simulation time 10000 fs, mesh auto non uniform with accuracy 4, minimum mesh step 0.00025 um, source centered at 1550 nm, source pulselength 150 fs.
This is my S parameter file.
Sparam.txt (884.7 KB)
Can someone please help me understanding why my response got active and the extinction ratio is so small for the through port? How can i fix this problem.
Thank you very much.