Orthogonality and normalization of radiation modes in dielectric waveguides: an alternative derivation

Abstract

Radiation modes in arbitrary dielectric waveguides with homogeneous cladding can be split into a free-space field having its sources at infinity and a scattered field excited by the polarization of the core region. In a recent paper, Sammut [ J. Opt. Soc. Am.72, 1335 ( 1982)] stated that radiation modes have the same orthogonality properties as their free-space parts in lossless waveguides. An alternative derivation is established, and connection with earlier work is also reviewed.