MoTe2-PVA as saturable absorber for passively Q-switched thulium-doped fluoride and erbium-doped fiber laser

Abstract

Passively Q-switched fiber lasers in the S- and C-band region were demonstrated using molybdenum ditelluride (MoTe2) as the saturable absorber (SA). The MoTe2 was prepared using liquid phase exfoliation method, which was then embedded in the polyvinyl alcohol (PVA) polymer to form a MoTe2 thin film SA. By incorporating the MoTe2 SA in the thulium-doped fluoride fiber laser (TDFFL) and erbium-doped fiber laser (EDFL) cavities, stable Q-switched pulses were observed in the S-band and C-band region with microsecond pulse durations and tens of kilohertz repetition rate. The modulation depth and the saturation intensity of the MoTe2 SA were ∼ 38 % and ∼ 0.314 MWcm−2, respectively. The Q-switched operation can be tuned by employing a tunable bandpass filter (TBPF), covering the S-band and C-band region from 1453 nm to 1572 nm. Thus, the finding validates the feasibility of MoTe2 as a promising SA for a broadband optical applications.