Modeling and characterization of a dual-wavelength SOA-based single longitudinal mode random fiber laser with tunable separation

In this work, a novel Single longitudinal mode (SLM) dual-wavelength random fiber laser (DW-RFL) with narrow line-width and tunable separation between the two modes in the range 1.5 – 25 nm (187 GHz – 3.12 THz) is presented. The laser is based on Rayleigh backscattering in a standard single mode fiber of 2 km length acting as distributed mirrors and a semiconductor optical amplifier (SOA) acting as the optical amplifier. Two optical band pass filters are used for the wavelength selection, and two Faraday Rotator mirrors are used to sustain the stability of the two lasing wavelengths against fiber random birefringence. The measured line-width of each mode of the laser varies from 3 to 11.5 kHz with lasing wavelengths and SOA pump currents. The power and the wavelength stabilities at the peak power of each mode were also investigated.