Guilin Sun
Ansys Employee

This is a good question. When there are two sources, intterference will occur. TE and TM most of the time are not 100% pure, eg Ex dominanted mode can have minor Ey when the waveguide is along z.  When there are more than one source, the sourcepower will use their incoherent result, however the simulation is coherent. In this case, if it is not for a circularly-polarized mode, what is the purpose to have TE and TM modes at the same time? do they have the same effective index, or degenerated? if yes, in experiment how do you control them? if not, how do you control their relative initial phase? I would strongly suggest you to think those questions carefully before you do the simulation.