Linearly polarized low-noise Brillouin random fiber laser

A linearly polarized Brillouin random fiber laser (LP-BRFL) with distributed feedback along 2 km polarization-maintaining fibers (PMFs) is demonstrated. The laser was built up using a bidirectional pumping mechanism in an all-PMF configuration, yielding a radiation with 8% power efficiency and more than 25 dB polarization extinction ratio. A high lasing efficiency is achieved due to the polarization-matched Brillouin amplification and distributed feedback along kilometer long PMFs. The relative intensity noise and the thermal-induced frequency noise of this random laser have also been measured and compared to that of a custom single-mode-fiber-based random laser and a conventional phase-locked laser.