A VECTOR FINITE-ELEMENT METHOD WITH THE HIGH-ORDER MIXED-INTERPOLATION-TYPE TRIANGULAR ELEMENTS FOR OPTICAL WAVE-GUIDING PROBLEMS

A vector finite element method with the high-order mixed-interpolation-type triangular elements is described for the analysis of optical waveguiding problems. It is a combination of linear edge elements for transverse components of the electric or magnetic field and quadratic nodal elements for the axial one. The use of mixed-interpolation-type elements provides a direct solution for propagation constants and avoids spurious solutions. This approach can yield more accurate results compared with the conventional approach using the lowest order mixed-interpolation-type elements, namely, constant edge elements and linear nodal elements. The accuracy of this approach is investigated by calculating the propagation characteristics of optical rib waveguides. Results obtained for both E(x) and E(y) polarizations are validated using benchmark results produced by established methods.