Learning Forum

[amoghbs]

Hi,
I am trying to understand scattering loss for a 2nd TE mode in a bend when transitioning from a straight waveguide mode to a bent one with specific waveguide dimensions, 2.4um in width and 80nm in depth and bend radius of 50um. I did the simulations in both FDFD (mesh accuracy 4) and varFDTD (mesh accuracy 5) but I am getting different transmission even though I think both are identical otherwise. I expected both the results to be different but the difference in T is too big (29% - FDTD vs 85% - varFDTD) . The susbtrate in my sims in 7um silicon, with a 2um SiO2 layer on top, and a dielectric with refractive index of 2.27 with thickness of 220nm and finally the waveguidees on top made of the same dielectric. I have attached the image of the sim setup and cross sectional E field plots. Could you please help me with this?