Comprehensive study on the parameters affecting the line-width and stability of SOA-based SLM random fiber laser

We report several techniques affecting line-width and long-term stability of single longitudinal mode (SLM) random fiber laser (RFL) based on Rayleigh backscattering in a standard single mode fiber as distributed mirrors, and a semiconductor optical amplifier (SOA) as the gain medium. Three parameters were investigated; single mode fiber (SMF) length, the optical filter bandwidth, and the type of the cavity reflecting mirror. Line-width of the laser was measured at three values of SMF length; 100 m, 1 km, and 2 km. Impact of the optical filter bandwidth on the laser line-width was studied. Finally, long-term stability was characterized for two types of reflecting mirrors; a silver coated mirror, and a Faraday rotating mirror (FRM).