Guilin Sun
Ansys Employee
Please use a refractive index monitor to get the index profile and see if there is any place the value is not normal .
If FDE can give correct result, there is no reason EME does not, since EME use FDE as its mode solver. Please make sure both of them use the same mesh size, and the same simulation cross section.
In EME, x axis is the propagation direction. If in XZ it has strong E field, you may need to check if there is any field enhancement. Does the S parameter look normal? eg, power conserved abs(S)^2<1?
If there are non-propagating modes and occasionally there is power leakage to those modes. Much higher order modes do not contribute to propagation other than field continuity. You may also need to change the number of modes and see how it improves. Try fewer modes first.