TaSe2-based mode-locked fiber laser with four switchable operating states

Transition metal dichalcogenides (TMDs) have attracted considerable attention in electronics and photonics. Tantalum diselenides (TaSe2) as a member of TMDs has been employed for field effect transistors and all-optical switching, and its nonlinear optical response has also been investigated. However, the applications of TaSe2 in ultrafast fiber lasers have not been exploited. Here, TaSe2 deposited on D-shaped fiber is used as saturable absorber (SA) in Er-doped fiber laser, and four switchable operating states (bright solitons, dark solitons, bright-dark soliton pairs and their HML counterparts, as well as bright-dark-bright soliton pairs) are realized successfully. To the best of our knowledge, this is the first presentation of a mode-locked fiber laser with the TaSe2-based SA, and also the first study of bright and dark soliton properties of a TaSe2-based fiber laser. It is foreseeable that TaSe2 will become an appealing candidate for bright and dark soliton fiber lasers.