A multi-wavelength random distributed feedback fiber laser with a Sagnac loop mirror

A multi-wavelength random distributed feedback fiber laser consisting of a length of erbium-doped fiber, a 20-km-long single-mode fiber and a Sagnac loop mirror was demonstrated experimentally. Under the pump power was changed from 30 to 180 mW, variable channel number of 2 to 8 was achieved, meaning that wavelength competition caused by homogenous gain broadening in erbium-doped fiber was significantly suppressed. The laser shows several other advantages such as low-cost, low threshold pump power, low coherence and simple configuration.