An optical network comprises a bidirectional link connecting two nodes (1) through two optical fibers (3). Optical output signals from optical transmitters (7) in a node are provided to transponders (11) issuing optical signals of well-defined wavelengths to a power combiner (13), from which optical...http://www.google.fr/patents/US6915075?utm_source=gb-gplus-shareBrevet US6915075 - Protection of WDM-channels
