All-fiber mode-locked gigahertz femtosecond laser at 1610 nm using a self-developed long-wavelength gain fiber

Authors：Xiao, Yongbao; Kuang, Ludong; Hu, Xu; Ye, Yichen; Wang, Weichao^*; Lin, Wei; Ji, Yao; Wan, Jie; Yang, Changsheng; Xu, Shanhui; Wei, Xiaoming; Zhang, Qinyuan

Source：Optics Letters, 2022, 47(4): 981-984.

DOI：10.1364/OL.451374

We report a compact all-fiber passively mode-locked ultra-fast laser with a fundamental repetition rate of 1.6 GHz that uses a self-developed long-wavelength active fiber, i.e., a fluoro-sulfo-phosphate-based Er3+/Yb3+ co-doped fiber (only 6.2 cm in length). This active fiber can provide a net gain coefficient of 0.6 dB/cm at 1610 nm. The high-repetition-rate all-fiber mode-locked laser operates at a low pump power of only approximately 90mW. The mode-locked pulse train has a period of 625 ps and a 3 dB bandwidth of 7.0 nm, which can support a transform-limited pulse width of 390 fs.