Confined-doped active fiber enabled all-fiber high-power single-frequency laser
Wei Li, Yan Zhiping, Shuai Ren, Yu Deng, Yisha Chen, Pengfei Ma, Wei Liu, Liangjin Huang, Zhiyong Pan, Pu Zhou, Lei Si
Abstract
In this paper, we investigate the performances of an in-house fabricated confined-doped active fiber in the applications of all-fiber high-power single-frequency amplifiers. A 210-W single-frequency single-mode fiber laser is obtained directly, which confirms the excellent performance of the confined-doped active fiber for high-power single-mode operation. To further demonstrate the power scalability of the fiber amplifier, the strategy of applying a temperature gradient along the active fiber is investigated numerically and experimentally, and an up to ∼75% enhancement of the stimulated Brillouin scattering (SBS) threshold is achieved. As a result, a 368-W single-frequency fiber laser is obtained with the beam quality factor of M x 2 = 1.19, M y 2 = 1.26. Overall, the technique of the confined-doped active fiber provides a promising approach to scale the output power of single-frequency single-mode fiber lasers.