title: Tungsten disulphide for ultrashort pulse generation in all-fiber lasers.
abstract: Tungsten disulphide (WS2), which exhibits excellent saturable absorption properties, has attracted much attention in the applications of photonic devices. In this paper, WS2is applied for the preparation of a saturable absorber (SA). Using the pulsed laser deposition (PLD) method, WS2is deposited on the side surface of the tapered fiber. In order to obtain larger non-linearity of the SAs with evanescent wave interaction, the tapered fiber had a smaller waist diameter and longer fused zone. Gold film was deposited on the fiber-taper WS2SAs to improve their reliability and avoid oxidation and corrosion. Employing the balanced twin-detector method, the modulation depth of the fiber-taper WS2SAs was measured to be 17.2%. With the fiber-taper WS2SA, a generated pulse with 246 fs duration and a 57 nm bandwidth was obtained at 1561 nm. The electrical signal to noise ratio was better than 92 dB. To our knowledge, the pulse duration was the shortest among the reported all-fiber lasers with transition metal dichalcogenide (TMD) SAs. These results indicate that fiber-taper WS2SAs with smaller waist diameter and longer fused zone are promising photonic devices for ultrashort pulse generation in all-fiber lasers.
authors.affiliation: State Key Laboratory of Information Photonics and Optical Communications, School of Science, P. O. Box 91, Beijing University of Posts and Telecommunications, Beijing 100876, China. mlei@bupt.edu.cn.
authors.forename: Wenjun
authors.initials: W
authors.lastname: Liu
authors.forename: Lihui
authors.initials: L
authors.lastname: Pang
authors.forename: Hainian
authors.initials: H
authors.lastname: Han
authors.forename: Ke
authors.initials: K
authors.lastname: Bi
authors.forename: Ming
authors.initials: M
authors.lastname: Lei
authors.forename: Zhiyi
authors.initials: Z
authors.lastname: Wei