The present invention significantly improves the signal to noise ratio (SNR) in a passive optical array comprising sensors located in rungs between a distribution bus and a return bus. Erbium-doped optical fiber amplifiers are included in the buses proximate to each rung coupling to offset the coupler...http://www.google.com.au/patents/US6084233?utm_source=gb-gplus-sharePatent US6084233 - Optical sensor array having multiple rungs between distribution and return buses and having amplifiers in the buses to equalize return signals
