Hi Marton,
You are welcome! These solvers are slightly more complicated to use than FDE, but I am pretty sure you can learn them. If the dimensions, and especially the length of the waveguides are a few microns (only a few times greater than the wavelength), then I will recommend using FDTD. But if these waveguides are extremely long (hundreds of microns), then EME will be more suitable, as FDTD will require a large amount of compute power. Ansys offers short introductory courses on these solvers. You can find them at Ansys Innovation Courses: Ansys Innovation Courses. When you visit the page, you can select the category as "Photonics" to see a list of all availabe courses. From there, you can find both FDTD and EME. These videos are pretty short and easy to understand but I think they will be a food place to get some familiarity with the solvers. The we can discuss setting up your simulation.
Regards,
Amrita