ANALYSIS OF THIN-FILM WAVEGUIDES WITH REFRACTIVE INDEX FLUCTUATION USING COUPLED POWER EQUATIONS.

To discuss random coupling between modes in a dielectric thin-film waveguide from the ensemble average point of view, coupled power equations were derived which include reconversion from the radiation mode to the guided mode. These equations were applied to a thin-film waveguide with refractive index fluctuations and numerical examples were used for discussion of random coupling between guided and radiation modes.