▎ 摘　　要

This study reports a Q-switching-based, 2058-nm holmium (Ho) fiber laser incorporating a saturable absorber (SA) based on graphene oxide (GO). The SA was prepared with a side-polished fiber, while GO particles were deposited onto the fiber-polished surface to realize an all-fiber SA. A continuous-wave thulium-doped all-fiber laser, which was configured with a master-oscillator power-amplifier (MOPA) structure, was constructed as a pumping source. By inserting the fabricated SA into an all-fiber ring resonator based on 1-m length of Ho-doped fiber, Q-switched pulses could readily be obtained at a wavelength of 2058 nm. The pulse width was observed to vary from 2.01 to 1.56 mu s as the pump power was adjusted from similar to 759 to 1072 mW, while the repetition rate was tunable from 45.56 to 56.12 kHz. The maximum values of average optical power and pulse energy were measured as similar to 11.61 mW and 207.05 nJ, respectively, at a similar to 1072 mW pump power.