MODE INSENSITIVE WAVEGUIDE DEVICE

摘要

A waveguide structure includes a substrate, a waveguide film, and an overlay material in contact with the waveguide film. The overlay material nay also contact the substrate or the film may be disposed between the overlay and the substrate. The overlay material has a higher refractive index than the waveguide so that the ratio of the effective refractive indexes is substantially constant for all propagating modes supported by the waveguide.