SESAM $Q$ -Switched Ho3+-Doped ZBLAN Fiber Laser at 1190 nm

We report a semiconductor saturable absorber mirror Q-switched holmium (Ho³⁺)-doped ZrF₄-BaF₂-LaF₃-AlF₃- NaF fiber laser operating at ~1190 nm in a linear cavity. Stable Q-switched operation was established at a threshold pump power of 92.8 mW with a repetition rate of 26.1 kHz and a pulsewidth of 4 μs. The repetition rate increased and the pulsewidth decreased with an increasing pump power. When the pump power was increased to 830 mW, 800-ns Q-switched pulses with a pulse energy of 0.18 μJ at a repetition rate of 170 kHz were generated.