Extended novel slab model analysis of overlaid bent step‐index single‐mode fiber half‐couplers. I. Basic formalism and normal‐mode approach

Abstract

AbstractAn extended novel slab model (ENSM) in strong guidance approximation (SGA) is presented for the modal analysis of overlaid bent step‐index single‐mode fiber half‐couplers (OL‐BSSF) where now proper (bound) and leaky modes are included as well. Within the frame of ENSM and SGA a basic formalism is elaborated to evaluate the propagation characteristics as well as the dissipative and/or leakage propagation losses of OL‐BSSF structures in a great measure analytically. The powerfulness of the formalism is demonstrated on a six‐layered OL‐BSSF/ESW basic structure with a general three‐layered overlay (OL) where the BSSF structure is mapped modally by an equivalent slab waveguide (ESW) structure. Such a multilayered slab basic structure can describe the modal and optical features of all hitherto implemented configurations of all‐fiber in‐line components as special cases straightforwardly based on OL‐BSSF structures.