本文回顾了高功率全光纤侧面抽运耦合器的研究进展, 重点介绍了拉锥-熔合法制作的侧面抽运耦合器的基本原理、研究现状、面临挑战及解决方案。该方案可实现千瓦量级高抽运耦合效率高信号光通过率抽运/信号耦合器的制备, 是高功率全光纤侧面抽运耦合器的主流方案。结合已报道的理论和实验结果, 总结了该方案在制作工艺、损耗机理、性能提升等方面面临的挑战, 提出了将侧面抽运耦合器引入级联抽运光纤激光器的方案, 并将一种(2+1)×1侧面抽运耦合器成功应用于2.5 kW输出的级联抽运掺镱光纤激光器中。结果表明, 相比LD抽运, 在级联抽运中, 高亮度光纤激光作为抽运光源使耦合器在保证高抽运耦合效率的同时具有更高的功率承载能力。

In this paper, we present a general review of the development of a high-power all-fiber side-pumping combiner developed over the past few years. Our main focus is on the fundamental mechanism of operation, in addition to a review of the development and the challenges associated with the realization of a functional side-pumping combiner, which was fabricated using a tapered-fused technique. This technique can potentially be exploited as a side-pumping method because of its high coupling efficiency, high signal transfer efficiency, and its capability of handling high pump powers up to the kilowatt range. This review includes an overview of theoretical and experimental results, the challenges associated with fabrication, an investigation of the loss mechanism, and an overview of the performance improvement of the combiner. In summary, a new (2+1) ×1 side-pumping combiner for a 2.5 kW fiber laser based on tandem pumping is introduced. The presented results suggest that the side pumping combiner has a high power loading capability as well as a high coupling efficiency when applied in a tandem-pumping scheme, due to the high brightness of the fiber laser as the pump light source.