Silicon wire waveguiding system: Fundamental characteristics and applications

We demonstrate a remarkable improvement in the waveguiding characteristics of silicon wire waveguides, and show their application to functional optical devices. Applying a novel spot‐size converter consisting of an ultrathin silicon taper and a SiON waveguide, coupling losses between silicon wire waveguide and optical fiber were greatly reduced to just 0.5 dB/coupling. Propagation losses were also reduced to less than 3 dB/cm, by smoothing the surface of the waveguide core. Some functional devices, such as photonic crystals, ring resonators, and lattice filters, were tested and showed superior optical characteristics. Enhancement of nonlinear phenomena due to a high power density effect was also observed. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 89(3): 42–55, 2006; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/ecjb.20210