Influence of reflected radiation waves caused by large mode field and large refractive index mismatches on splice loss evaluation between elliptical-hole lattice core holey fibers and conventional fibers

When the mode field and refractive index mismatches between two spliced fibers are small, the splice loss is generally evaluated by calculating an overlap integral without reflection waves. A single-polarization circular-hole holey fiber with a core consisting of an elliptical-hole lattice (EC-CHF) has a strikingly different mode field caused by elliptical holes in the core region from those of conventional single-mode fibers (SMFs), and thus reflected radiation modes may significantly appear in splicing an EC-CHF to conventional SMFs. We study the influence of reflected radiation modes on the splice loss evaluation of optical fibers with large mode field and large refractive index mismatches through numerical analyses using a bidirectional eigenmode propagation method and a three-dimensional finite-element method. (C) 2013 Optical Society of America