Overlay Parameters Research Articles

Extended novel slab model analysis of overlaid bent step‐index single‐mode fiber half‐couplers. II. Coupled‐mode approach and design of overlays

AbstractWe present for the modal analysis of overlaid bent step‐index single‐mode fiber half‐couplers (OL‐BSSF) a coupled‐mode approach where the overlay (OL) and the BSSF structure are analyzed in isolation and the design criterion of suited BSSF and OL parameters is based on the phase‐matching condition of the coupled‐mode theory. The BSSF is mapped modally by an equivalent slab waveguide (ESW) structure. For the OL structure a general three‐layered overlay is considered which takes into account lossless, lossy, leaky, and plasmon active properties. Analytical expressions for the propagation characteristics of bound, bound surface plasmon polariton (SPP), leaky, and leaky SPP overlay modes are derived on which OL parameters at given BSSF/ESW parameters can be designed.