Stabilized High-Order Mode Brillouin Random Fiber Laser Using a Self-Matched Dynamic Fiber Grating

We propose and experimentally demonstrate a stable high-order mode (HOM) Brillouin random fiber laser based on randomly distributed Rayleigh scattering in few-mode fibers. Taking advantage of a few-mode erbium-doped fiber-based dynamic fiber grating with self-matched spatial mode, mode hopping of HOM Stokes random laser can be significantly suppressed, benefiting prominent intensity noise reduction and laser frequency stabilization. Results show that, the power fluctuation of the proposed laser with few-mode dynamic fiber grating is reduced by 50%, while the variance of the laser frequency fluctuations within 1000 milliseconds has been optimized down to 0.15. Notably, the LP11 mode of the laser output achieves a purity exceeding 95% with fluctuations reduced by 56.9%. It is believed that the proposed HOM laser would be promising for applications in optical fiber communication and fiber sensing.