Size effect of WSe2 on red passively Q-switched fiber laser output performance

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 (WSe2)-based red Q-switcher is fabricated and successfully used for Q-switched pulse generation in a red Pr3+-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 WSe2 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.