Induced polarization effects in coupling processes of waveguide modes

An analysis of waveguide problems based on a solution of full vector-wave equations is very important for many applications. To solve such problems, a new coupled-mode method, taking into account the so-called induced polarization effects, is proposed in this paper. The theory is based on the spectral method, which makes it possible to analyze correctly a mode excitation by arbitrary sources with longitudinal components. It also takes into consideration singularities caused by abrupt discontinuities of longitudinal currents. The method may be a powerful tool for investigation of propagating and evanescent modes coupling due to both material and geometric effects.