A Wavelength Division Multiplexing (WDM) optical monitor, based on concatenated fiber gratings, uses a single modulator and detector and has high dynamic range and good sensitivity through signal averaging. The WDM optical monitor may be implemented in a time-domain or frequency-domain embodiment and...http://www.google.de/patents/US5995255?utm_source=gb-gplus-sharePatent US5995255 - Concatenated fiber grating optical monitor
