FINITE-CLADDING FIBERS - HE12 AND LOCAL-NORMAL-MODE COUPLING EVOLUTION

A discussion of the evolution of the HE12 (LP02) field, and thus the role of the core in HE11-H12 (LP01-LP02) local-mode coupling for a tapered 'doubly-clad' lightguide as may be formed by the combination finite-cladding fibre and external medium (i.e. outer cladding) is presented. Consideration of more than one interface injects interesting novel features into the local-normal-mode viewpoint: examination of the HE12 lobe maximum and field evolution leads to the discovery of a core/cladding bounce phenomenon (related to an HE12 leaky-mode property) as well as an intriguing coupling phase dependence.