The computation of the reflectivity of a multilayer dielectric coating deposited on the end facet of single-mode or multimodal fiber is presented. The calculation is done through a plane-wave expansion of the incident fields, and the waveguide is replaced by a homogeneous medium of refractive index n<sub>eq</sub> while the incident electric (or magnetic) field remains that of the guided mode. The modal reflectivities (coupling factors) between modes are calculated, and the method of computation is accurate enough to satisfy current needs for the design of coatings on fibers and is helpful for the design of coatings deposited on other waveguide structures.
© 1998 Optical Society of America
(060.2270) Fiber optics and optical communications : Fiber characterization
(120.2440) Instrumentation, measurement, and metrology : Filters
(230.7370) Optical devices : Waveguides
(310.1620) Thin films : Interference coatings
O. Vasseur, "Reflectivity of dielectric coatings deposited on the end facet of a weakly guiding fiber," J. Opt. Soc. Am. A 15, 77-83 (1998)