Abstract

Transition metal dichalcogenides (TMDs) possess a direct bandgap in the visible frequency range and can be applied as attractive visible saturable absorbers (SAs). In this paper, a new TMDs tungsten selenide (${\mathrm{WSe}}_2$)-based red $Q$-switcher is fabricated and successfully used for $Q$-switched pulse generation in a red ${\mathrm{Pr}}^{3+}$-doped ZBLAN fiber laser. The passive $Q$-switching fiber laser at 635.2 nm generates a stable pulse with pulse duration of 504 ns and average output power of 4.91 mW as well as a tunable pulse repetition rate of 131.9–260.4 kHz. Furthermore, the size effect of ${\mathrm{WSe}}_2$ on the 635 nm passive $Q$-switching output performance is also investigated. Our work will provide certain significance for the optimization of passive $Q$-switching red fiber lasers based on TMDs.

© 2018 Optical Society of America