Low loss shallow-ridge silicon waveguides.

We demonstrate low loss shallow-ridge silicon waveguides with an average propagation loss of 0.274 + or - 0.008 dB/cm in the C-band (1530 nm - 1565 nm). These waveguides have a cross section of 0.25 microm by 2 microm and are fabricated by standard photolithography and dry etching. We also investigate a compact double-level taper which adiabatically couples light from these waveguides to silicon strip waveguides enabling tight bends.