Array waveguide gratings

Summary form only given. Fundamental operational principles and key features of AWGs are described. Then, the current performance and future prospects of AWGs and planar lightwave circuits (PLCs) are discussed. Channel numbers of AWGs have dramatically increased up to 400 ch in single wafers. In multi-chip configurations (tandem AWGs), 1010 ch has been achieved with 10 GHz channel spacing. Although throughput of the transport can be increased to the tera-bit level by WDM technology, signal processing in the electrical layer becomes a serious problem due to its speed limit. Optical functional devices, therefore, are important for solving these issues. Various kinds of optical-layer signal processing devices such as N/spl times/N wavelength routers, dispersion-slope equalizers, PMD equalizers, temporal pulse shapers and optical label recognition circuits are described. AWG-based devices for ultra-high bit rate light pulses are compared with those for telecom applications.