Effects of cores in fused tapered single-mode fiber couplers

Fused tapered single-mode fiber couplers are analyzed in detail by the simple effective-index method. It is found that the core parameters of the coupler, i.e., the core-cladding radius ratio, the core-cladding profile height, and the core separation, can have significant effects on the coupler characteristics. In practice, neglect of the cores as in many previous studies may lead to intolerable errors. © 1987 Optical Society of America.