▎ 摘　　要

A 1.3 m Q-switched fibre laser using a praseodymium doped fluoride fibre and a polyvinyl alcohol (PVA)/graphene based saturable absorber (SA) is proposed and demonstrated. Stable Q-switched outputs are obtained over a pumping range between 472.4 and 567.2 mW at 1.02 m. A pulse repetition rate and pulse width of 34.86 kHz and 3.50 s, respectively, is obtained at a maximum pump power of 567.2 mW along with an average output power of 25 mu W and output energy of 0.73 nJ. The Q-switched pulses have a 1.8 nm full width at half maximum and 32 dB signal-to-noise ratio.