17-Ghz Waveguide Lasers Modulated by a Heterostructure Layered Material

In this work, a thin-film MoS2/WS2/MoS2/WS2 heterostructure is employed as a saturable absorber (SA) material for efficient ultrafast pulsed laser operation, achieving a 17.54 GHz Q-switched mode-locked Nd:GGG waveguide laser fabricated by femtosecond laser direct-writing (FsLDW). The mode-locked pulse duration is measured to be as short as 31 ps. The maximum laser slope efficiency and the average output power are determined to be 29.27% and 310 mW, respectively. Such a high-performance compact pulsed laser exhibits promising applications of crystalline waveguide structures and layered heterostructures in ultrafast integrated photonics. This work represents the very first experimental demonstration of a pulsed laser based on FsLDW Nd:GGG waveguides and the very first demonstration of using a MoS2/WS2/MoS2/WS2 heterostructure as an efficient SA.