Stimulated Brillouin Scattering Fiber Laser with Effective Suppression of the Number of Longitudinal Modes

A method to significantly suppress the number of oscillating longitudinal modes in a long cavity Brillouin fiber laser is proposed and experimentally demonstrated. A stimulated Brillouin scattering fiber laser (SBS-FL) with a laser configuration composed of a 1 km SMF-28 fiber as the SBS gain medium to obtain strong SBS and a 100 m SMF-28 tapered fiber to obtain enough stimulated Rayleigh scattering feedback to decrease the number of longitudinal modes significantly is constructed. With the mode suppression effect, the RF beating noise of the laser output can be suppressed obviously, and a Brillouin laser output with high stability and high OSNR is obtained. The proposed SBS-FL will have great potential in pure microwave signal generation researches.