MoO_3-x as a wideband optical saturable absorber for passively Q-switching ytterbium-, erbium-, and thulium-doped fiber lasers

Wideband optical saturable absorbers (SA) are an ideal laser component for pulse laser generation in different wavelengths, which has attracted tremendous attention in recent years. Herein, a MoO_3-x-based novel wideband optical SA has been demonstrated by utilizing it for ∼1/1.5/2 μm Q-switched pulses generation. After separately integrating the MoO_3-x-SA into Yb-, Er- and Tm-doped fiber lasers, passively Q-switched pulses with pulse durations of ∼1.5/2.2/1.6 μs, repetition rates of several tens kilohertz at corresponding wavelengths of ∼1038/1562.9/1910 nm are obtained. Our work firstly reveals the remarkable wideband optical saturable absorption of the MoO_3-x, which strongly implies the potential application in infrared photonics devices. It may also provide new opportunities for wideband optical SA based on oxygen-deficient metal oxides.