Tunnel and diffraction excitation of optical waveguides prepared by diffusion

A theoretical analysis is made of the processes of tunnel and diffraction mechanisms of the emission of surface waves from diffused waveguides with an arbitrary transverse distribution of the refractive index. The reciprocity principle and effective parameters (thickness h_m* and refractive index n_m* ) are used in the determination of the optimal conditions for the excitation of diffused waveguides.