A PRACTICAL PASSIVE SURVEILLANCE SCHEME FOR OPTICALLY AMPLIFIED PASSIVE BRANCHED OPTICAL NETWORKS

We propose and experimentally demonstrate a novel and practical survei llance scheme for in-service fault identification in passive optically amplified branched networks, This scheme does not require any wavelen gth-tunable light source as used in multiwavelength optical time-domai n reflectometer (OTDR), Fiber-Bragg gratings are placed at some strate gic positions on different fiber branches to slice and reflect the opt ical amplifier's residual amplified spontaneous emission (ASE) power a t some wavelengths other than the signal wavelengths, The conditions o f the fiber link and optical amplifier at each branch can be monitored by constantly checking the reflected power level of the corresponding wavelength without suspending the in-service channels.