DIRECTIONAL COUPLER BASED ON RADIATIVELY COUPLED WAVE-GUIDES

We investigate a system of two waveguides with leaky modes sharing a c ommon substrate (radiatively coupled waveguides). The main advantage o f such a system is the possibility of remote coupling. A perturbation theory is developed for both TE and TM polarization. Numerical calcula tions of dispersion curves and of the coupling length allow us to dete rmine the limitations of the perturbation theory. We study the influen ce of multimode interference on the process of beating by considering the propagation of a given initial field. Finally, we propose a new de sign for an effective, integrated optical TE-TM polarization splitter. (C) 1997 Optical Society of America