INTEGRATED OPTICAL CIRCUIT TECHNOLOGIES

Various kinds of optical circuit are required for constructing optical communication systems with higher transmission efficiency and network flexibility. These circuits include optical splitters, optical switches, wavelength-division multiplexers as well as integrated light sources and detectors. This paper describes two integrated-optic approaches to optical network construction currently being investigated at NTT Laboratories. They are (1) a planar lightwave circuit approach, using low-loss SiO2 waveguides on Si substrates as passive optical circuits, and (2) a monolithic semiconductor approach, based on III-V compounds such as InP, to realize active optical circuits.