▎ 摘　　要

A Q-switched S-band thulium fluoride fiber (TFF) driven by a 1400 nm laser diode is proposed and demonstrated. The TFF has the advantage of being pumped at 1400 nm, which is an easily available and relatively low-cost pump source, as opposed to conventional pumping at 1050 nm. It has a gain profile from 1440 nm to 1520 nm, and Q-switching is realized with the use of a thin film graphene saturable absorber. The Q-switched TFF laser exhibits a maximum repetition rate and minimum pulse width of 36.3 kHz and 3.2 mu s respectively, as well as an average output power and pulse energy of 0.76 mW and 20.9 nJ at a maximum pump power of 230.4 mW. The output pulses are highly stable, and to the best knowledge of the authors this is the first demonstration of a Q-switched TFF laser pumped at 1400 nm.