Ray invariants, plane wave spectra, and adiabatic modes for tapered dielectric waveguides


  • J. M. Arnold,

  • L. B. Felsen


In nonseparable problems resulting from the analysis of wave propagation in longitudinally varying waveguides, such as a wedge-shaped taper, singularities appear in both ray and coupled mode treatments at the local normal mode cutoff transition. A uniformization of the local normal (adiabatic) mode is proposed, using plane wave spectra, which effectively resolves this difficulty.