Single-longitudinal-mode Brillouin random fiber laser with high linewidth-compression ratio and laser efficiency based on distributed intrinsic feedback mechanism

A single-longitudinal-mode (SLM) Brillouin random fiber laser with high linewidth-compression ratio and laser efficiency was achieved in this work. With the assistance of the distributed intrinsic feedback mechanism structure (DIFMS) and Brillouin amplification, the maximum linewidth-compression ratio of the fiber laser could be as high as 334 when a broader pump laser with 1 MHz linewidth was used. The formation process of linewidth compression and SLM laser output was also theoretically analyzed. The fiber laser exhibited a high laser efficiency of 21.5% owing to the enhanced Rayleigh scattering fiber (ERSF), which acted as the key element of DIFMS. In addition, the fiber laser with ERSF showed a flexible wavelength tunability from 1535 nm to 1565 nm and a good temporal stability with the maximum power fluctuation of less than 0.3 dB during an hour. These results revealed that the proposed DIFMS applicable to other gain-type lasers as a mechanism structure has great applications in suppressing longitudinal modes and further compressing the linewidth of laser.

Automated summary

A single-longitudinal-mode Brillouin random fiber laser with high linewidth-compression ratio and laser efficiency was achieved in this study. The theoretical analysis and experimental results showed the potential of the proposed distributed intrinsic feedback mechanism structure and Brillouin amplification in suppressing longitudinal modes and compressing the linewidth of the laser.