Hi, I am looking into some simulations of rib waveguide structures using Finite Element Method. I particularly solving modes for a 2D cross section of the optical waveguide, looking at TE and TM modes. My questions is about modes called "degenerate" and "hybrid" modes. I haven't found any information what is a "degenerate" or "hybrid" modes are. Any one knows about this? Can two modes interact/interfere with each other if the effective refractive indices of the mode are the same for different orders of the mode of TE and TM?