Analytical calculation of cutoff wavenumbers of dielectric waveguides with elliptical cross section

Abstract

The cutoff wavenumbers of the elliptical dielectric waveguide are obtained through analytical expressions, when the eccentricity h of the elliptical core is specialized to small values. In this case, analytical, closed-form algebraic expressions, free of Mathieu functions, are obtained for the cutoff wavenumbers. These expressions are valid for every different value of the indices s and n, corresponding to every higher-order hybrid mode. Numerical results are given for various higher-order modes, as well as a comparison with the exact solution.