Transmission Higher than One from Straight Strip Waveguide

fdtd
diverge

#1

Hi all,

After finishing the 3D FDTD simulation of straight waveguide for lengths higher or equal to 100 um, I have noticed that I get transmission higher than one which is not normal. I guess that is due to a numerical error from the simulator. Can you please confirm that and solve this issue as other work depends on it?

Strip WG


#2

Hi @mohamedmansour

Please use a few frequency points for the number of modes in mode source:
https://kb.lumerical.com/en/ref_sim_obj_mode_source_-_broadband.html

Also increase the z-span to, say 3um, and make sure that fields are decayed 5 orders of magnitude before reaching PML. The simulation span is quite long and you can run it in your machine.

Thanks


#3

Here is the result that I obtained by running your simulations overnight:

image

This confirms that transmission is 1 withing numerical errors of 0.1%.