Hi Guilin,

Thanks for your reply. Before doing FDTD simulation, I did fiber to waveguide edge coupling. From fiber to taper end edge coupling, I get efficiency of 90% between TM mode of fiber and first TM mode of the taper end.


So for FDTD simulation, should I take mode source into account with first TM mode simulation at the start of the taper rather taking Gaussian source? Will it be a correct approach?