3d rcwa

Hi, anyone knows how to calculate dispersion curve and transmission/reflection of 3D dielectric waveguide by RCWA? What's the difference between 3D-RCWA and 2D-RCWA? How to apply PML in this method?

I have read Phillipe Lalanne's paper on photonic crystal waveguide calculation. But I don't know how to use this method. Anyone can help me? Thanks!

rumpf, can you give me some advice to simulate 3d dielectric waveguide or photonic crystal slab by Fourier modal method (FMM) or named rigarous coupled wave method (RCWA)?
Thanks.