5 kW power-level 1050 nm narrow-linewidth fiber amplifier enabled by biconical-tapered active fiber
Pengfei Ma, Zhiyong Pan, Tianfu Yao, Huan Yang, Yisha Chen, Wei Liu, Xiaolin Wang, Zefeng Wang, Pu Zhou, Jinbao Chen
Abstract
Effective wavelength extension is vital in the applications of high-power narrow-linewidth fiber lasers. In this work, we demonstrate a 5-kW power-level narrow-linewidth fiber amplifier at 1050 nm utilizing a homemade biconical-tapered Yb-doped fiber (BT-YDF). Up to ∼4.96 kW fiber laser is achieved with a 3 dB linewidth of ∼0.54 nm and a beam quality factor of M x 2 = 1.46, M y 2 = 1.6. The experimental comparisons reveal that BT-YDF has the advantages of improving a stimulated Raman scattering threshold and balancing transverse mode instability suppression in the fiber amplifier. This work could provide a good reference for extending the operating wavelength of high-power fiber amplifiers.