45 W kHz-linewidth single-frequency fiber laser at 1120 nm

Single-frequency fiber lasers (SFFLs) at 1120 nm have been widely used in biochemical analysis applications by generating 560 nm lasers. Here, we investigate the capacity of large-mode-area Yb-doped fiber for 1120 nm single- frequency laser amplification. By optimizing the length of large-mode-area Yb-doped fiber to balance the amplified spontaneous emission and stimulated Brillouin scattering effect, the output power of the 1120 nm SFFL could be enhanced to 45 W with a slope efficiency of 59.9%. At the maximum power level, the optical signal-to-noise ratio, the linewidth, and the beam quality of the output laser are 45 dB, 7.03 kHz, and M x 2 = 1.52/My2 = 1.49, respectively. Our study proves that using large-mode-area fiber in cooperation with a gain coefficient and fiber length optimization is promising to improve the output power of 1120 nm SFFL. And the experimental results provide implications for the expansion of Yb-doped single-frequency lasers to the wavelength above 1100 nm. (c) 2024 Optica Publishing Group. All rights, including for text and data mining (TDM), Artificial Intelligence (AI) training, and similar technologies, are reserved.