REFLECTIVITY OF DIELECTRIC COATINGS DEPOSITED ON THE END FACET OF A WEAKLY GUIDING FIBER

The computation of the reflectivity of a multilayer dielectric coating deposited on the end facet of single-mode or multimodal fiber is pres ented. The calculation is done through a plane-wave expansion of the i ncident fields, and the waveguide is replaced by a homogeneous medium of refractive index n(eq) while the incident electric (or magnetic) fi eld remains that of the guided mode. The modal reflectivities (couplin g factors) between modes are calculated, and the method of computation is accurate enough to satisfy current needs for the design of coating s on fibers and is helpful for the design of coatings deposited on oth er waveguide structures. (C) 1998 Optical Society of America.