Refracted near-field measurements of refractive index and geometry of silica-on-silicon integrated optical waveguides

The standard refracted near-field technique for measuring the refractive-index profile of optical fibers cannot be directly used for silica-on-silicon integrated optical waveguides because of the opacity of silicon. A modified method is thus presented to characterize this kind of waveguide. The resolution it gives, both spatially and in the refracted index, is practically as good as that obtained with the standard technique for measuring optical fibers.