Suppression of stimulated Brillouin scattering in optical fibers by tilted fiber Bragg gratings

Opt Lett. 2020 Sep 1;45(17):4802-4805. doi: 10.1364/OL.401433.

Abstract

Stimulated Brillouin scattering (SBS) has significant influence on optical fiber communication (OFC), optical fiber sensing (OFS), and narrow-linewidth fiber laser (NLFL) systems. How to effectively suppress it has always been a challenge. In this Letter, we propose and demonstrate a versatile solution, for the first time, to the best of our knowledge, by using tilted fiber Bragg gratings (TFBGs). A specially designed and fabricated TFBG can be used as an ultra-narrow spectral filter, precisely matching with the operation laser wavelength and the tiny frequency shift due to SBS. Experimental results show that the backward Stokes can be strongly rejected with a filtering ratio of >10dB; meanwhile, an obvious increasing of SBS threshold is observed with a maximum value of 1.7 times that without the TFBG, which enhances the effective transmission power by 33%. The operation stability of this method also is validated. This work opens new opportunities for SBS suppression in OFC, OFS, and high-power NLFL systems.