An optical telecommunications system node terminates a plurality of optical cable routes. Each of the optical cable routes includes a traffic route and a restoration route. The node includes a plurality of traffic wavelength division multiplexers and a plurality of restoration wavelength division multiplexers....http://www.google.com.tw/patents/US6061482?utm_source=gb-gplus-share專利 US6061482 - Channel layered optical cross-connect restoration system
