Silicon optical waveguides with buried-CoSi_2 cladding layers

Abstract
We report a new Si waveguide that has a buried, metallike cladding. Infrared light propagates in a crystal Si layer atop a 50-nm film of buried CoSi2 formed by implantation. Experiments in a 20-μm Si structure at the 1.3-μm wavelength show propagation losses below 2.5 dB/cm for TE0 and TM0. Results agree with theory. We also constructed two vertically integrated Si slab waveguides bounded below by CoSi2 cladding layers.