abstract
- We demonstrate by numerical simulations and experiments that highly reflective (HR) facets can be formed on silicon waveguides with high reflectivity diffraction gratings. We use an HR grating with a plane wave reflectivity exceeding 99.99%, as calculated by rigorous coupled wave analysis. Experimentally, we demonstrate the HR effect for silicon-on-insulator waveguide facets patterned lithographically with grating structures. Due to a strong mode size dependence, the maximum facet reflectivity for 1.5 microm thick waveguide is 77%, but finite difference time-domain simulations show that modal reflectivies larger than 90% can be achieved for silicon waveguides with thicknesses of 4 microm or more.