Silica-based Single-Mode Guided-Wave Devices

Silica-based single-mode waveguides, fabricated on silicon substrates by a combination of flame hydrolysis deposition and reactive ion etching, have low propagation loss and low fiber coupling loss. High controllability in the silica-based waveguide fabrication leads to directional couplers with an accurate coupling ratio can be fabricated. Based on these advantageous features, we have successfully constructed a variety of guided-wave devices such as multi/demultiplexers for 1.3 and 1.55 μm wavelength, 2 x 8 couplers, ring resonators, and Mach-Zehnder interferometers which operate as optical switches or multi/demultiplexers with various channel spacings from 0.008 nm to 0.25 μm.