▎ 摘　　要

We report Q-switched pulse operation of holmium (Ho3+)-doped ZrF4-BaF2-LaF3-AlF3-NaF (ZBLAN) at similar to 1190 nm in an all-fiber ring laser by using a fiber-optic graphene saturable absorber, which was fabricated by depositing graphene onto the flat surface of a side-polished D-shaped fiber. Stable Q-switched operation was established at a pump power of 180 mW with a repetition rate of 24 kHz and pulse width of 5.7 mu s. When the pump power was increased to 1125 mW, 0.44 mu J Q-switched pulses with a repetition rate of 111 kHz and a pulse width of 0.8 mu s were generated. (C) 2015 Optical Society of America