ANISOTROPIC RECTANGULAR WAVEGUIDES WITH DIAGONAL INDEX TENSORS, APPROXIMATE VARIATIONAL ANALYSIS WITH ANISOTROPY AS A PERTURBATION

摘要

The eigenvalue equation of anisotropic rectangular dielectric waveguides with diagonal index tensors is decomposed into a pair of scalar wave equations coupled only because of anisotropy. We solve the approximate, uncoupled equations by variational analysis and handle the coupling term as a first-order perturbation. We prove the stationarity of the scalar variational expression also for discontinuous (''vectorial'') mode functions. Computed propagation constants agree to 3-6 significant digits with published finite-element results. [References: 8]