Frequency-stabilized and high-efficiency Brillouin random fiber laser based on a fiber Bragg grating ring

A high-efficiency Brillouin random fiber laser (BRFL) with high frequency stability based on fiber Bragg grating ring (FBGR) is proposed and demonstrated. The FBGR consists of a section of single-mode fiber, a 2 x 2 optical coupler and a fiber Bragg grating, acting as a narrowband filter with enhanced reflection to filter out numerous random modes. The filtering ability of the FBGR is theoretically analyzed and experimentally validated. In the experiment, the relative intensity noise and the statistical analysis of mode hopping of the FBGR-based BRFL indicate that the suppression of multi-mode resonance and mode competition. As a result, a frequency drift of 0.307 MHz is achieved in the FBGR-based BRFL with a high laser efficiency of 50.6 %. Such an efficient and frequency-stabilized BRFL shows great potential for practical applications in coherent communication and optical sensing.