An optical wavelength selector is provided that selects WDM channels from WDM optical signal and outputs each WDM channels from a plurality of ports. WDM optical signal in which m.times.n WDM channels are multiplexed is divided into n WDM channel groups and outputted by means of one wavelength-division...http://www.google.com/patents/US6271949?utm_source=gb-gplus-sharePatent US6271949 - Optical communication system using wavelength-division multiplexed light
