Prospects and challenges for microphotonic waveguide components based on Si and SiGe

Optical properties of silicon-on-insulator (SOI) and SiGe waveguides are reviewed. Design and fabrication challenges are highlighted in view of the demand for downscaling of waveguide circuits. Scaling laws governing the mode number, optical power isolation, bend loss, effective index and the birefringence are discussed, for waveguide dimensions ranging from several microns down to sub-micron scale. In particular, variations in the effective …