▎ 摘　　要

We report on the first Tm3+-doped double tungstate waveguide laser passively Q-switched by a graphene saturable absorber using a 12.4 mu m-thick 3 at.% Tm:KY0.58Gd0.22Lu0.17(WO4)(2) epitaxial layer grown on a (0 1 0)-oriented pure KY(WO4)(2) substrate. This laser generated 5.8 nJ/195 ns pulses at 1831.8 nm corresponding to a pulse repetition frequency of 1.13 MHz. These are the shortest pulses achieved in passively Q-switched Tm waveguide lasers. The laser slope efficiency was 9% and the Q-switching conversion efficiency reached 45%. Graphene is promising for the generation of ns pulses at similar to 2 mu m in Tm3+-doped double tungstate waveguide lasers operating in the MHz-range.