Fiber-fault identification for branched access networks using a wavelength-sweeping monitoring source

We propose and experimentally demonstrate a new fiber-fault identification scheme for optically amplified branched networks. The scheme makes use of fiber Bragg gratings and an internally generated light source from erbium-doped fiber amplifiers through an optical feedback loop, and no additional dedicated monitoring source is required. The monitoring technique invokes both frequency and time domain by sweeping the wavelength of the monitoring source. By combining with a conventional optical time-domain reflectometer technique, exact location in fiber cut in branched network can be identified readily.