1State Key Laboratory of Information Photonics and Optical Communications, School of Science, Beijing University of Posts and Telecommunications, Beijing 100876, China
2Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
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 μm 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 μm.