Hi , my name is James i’ve been trying to Model a Ring resonator, with 2.5D, 3D and also with the SiEPIC Library Model to compare with my experimental results. and i have some questions.–the complete report and questions is in this link:
Report -Ring Resonator Analysis and Questions.
• Why it is the SiEPIC library model more accurate than the 3D model for the Q value? Is it because of mesh accuracy or a script is apply to obtain a more realistic behaviour?
• Considering what the Lumerical’s 2.5D FDTD Propagation Method  says about considering negligible the slabsmodestocalculatetheeffectiveindex.Itspossibleto obtain a more accurate results in 2.5D simulations if the geometry used would allow a more pure TE-like mode, for example 440 nm of width and 180 of thickness?
• In order to measure the thermo-optic response, how can a temperature variation can be simulated in FDTD solutions?