Attenuation characteristics of single-mode metal-clad graded-index waveguides with a dielectric buffer: a simple and...

We present a simple and accurate numerical method for the determination of the complex propagation constants of metal-clad graded-index planar waveguides with arbitrary refractive-index profiles. Numerical results for practically important profiles such as exponential and Gaussian are presented and compared with the homogeneous core waveguides. The analysis should find application in the design of high-differential-attenuation metal-clad polarizers, in reducing losses in integrated-optic modulators using metal electrodes, and in other devices using metal overlays.