ANALYSIS OF OPTICAL WAVE-GUIDE STRUCTURES COMBINING CYLINDRICAL AND PLANAR STRUCTURES BY A SIMPLE PERTURBATIVE METHOD

A simple perturbative method is proposed for the study of optical waveguide structures formed by a cylindrical fiber coupled to a planar substructure limited by an external medium with a refractive index below the fiber cladding level. The method is applied to the analysis of a structure including a thin metal layer deposited on the surface of a side-polished fiber. The comparison between theoretical and experimental results shows that the method provides an explanation and an accurate description of the resonant coupling between the fiber mode and a surface plamon wave in the metal film.