当前窄线宽光纤激光器的输出功率已经达到数千瓦,但是受激布里渊散射(SBS)仍然是制约其功率提升和系统稳定性的主要因素。基于倾斜光纤Bragg光栅(TFBG)对SBS产生的后向斯托克斯(Stokes)光的滤波作用,实验验证了TFBG对SBS的抑制作用。将经优化设计并制备的倾斜光纤光栅置于单模光纤放大器和一段长150 m的单模传能光纤之间,发现后向传输的Stokes光的滤除率接近10 dB,同时观测到了明显的SBS阈值提升,阈值约为不加TFBG时的1.25倍,前向输出的信号功率提升了约20%。该研究对于高功率窄线宽全光纤激光器的功率提升具有积极的作用,同时在光纤通信和光纤传感中也有潜在的应用价值。

Currently, narrow linewidth fiber lasers with output powers of several kilowatts have been developed; however, their power improvement and system stability are still majorly restricted by stimulated Brillouin scattering (SBS). Based on our previous verification, the tilted fiber Bragg grating (TFBG) can effectively filter the backward-propagating Stokes wave owing to SBS in fibers. This study further verified its suppression effect on SBS through experiments. With an optimized and fabricated TFBG being inserted between a single-mode fiber (SMF) amplifier and a 150-m-length single-mode energy-transmitting fiber, the backward-propagating Stokes wave is strongly rejected with a filtering ratio of approximately 10 dB. Meanwhile, an obvious increasing of the SBS threshold is observed with a value 1.25 times than that in the case without the TFBG, which increases the effective laser output power by approximately 20%. This study provides new insights into the SBS suppression in fibers. Furthermore, it is extremely useful in the further power scaling of high-power narrow bandwidth all-fiber lasers. It also has potential applications in fiber-optic communication and fiber-optic sensing.