Q-switched fiber laser operating at 1.5 μm based on WTe2

Compared with the extensively studied MoS2 and WS2, WTe2 owns a smaller bandgap, which is applicable to a near-infrared system in photodetectors, communications, and ultrafast optics. In this work, the WTe2 saturable absorber (SA) with the tapered fiber structure is prepared by the magnetron-sputtering technology, which enables the prepared SA to be low in cost and have strong nonlinearity. The modulation depth of the prepared WTe2 SA is measured as 31.06%. The Q-switched fiber laser operating at 1.5 mu m is successfully investigated by incorporating the proposed SA into the prepared ring cavity. To the best of our knowledge, this is the first attempt of WTe2 in the Q-switched fiber laser at 1.5 mu m.