Silicon optical waveguides with buried-CoSi(2) cladding layers

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 CoSi(2) formed by implantation. Experiments in a 20-microm Si structure at the 1.3-microm wavelength show propagation losses below 2.5 dB/cm for TE(0) and TM(0). Results agree with theory. We also constructed two vertically integrated Si slab waveguides bounded below by CoSi(2) cladding layers.