Niobium telluride absorber for a mode-locked vector soliton fiber laser

Niobium telluride(NbTe2),an emerging transition metal dichalcogenide material,has been theoretically predicted to have nonlinear absorption properties and excellent optical response.However,only a few studies of the utilization of NbTe2in ultrafast photonics have been reported.In this work,a NbTe2-based saturable absorber(SA) was applied in an erbium-doped fiber as a mode-locked device,and a vector soliton based on NbTe2was obtained for the first time.NbTe2-PVA film SA was successfully prepared by the liquid-phase exfoliation and spin coating methods,with a modulation depth of up to 10.87%.The nonlinear absorption coefficient of NbTe2-based SA film tested through the open-aperture Z-scan laser measurement is 0.62×10-11m/W.A conventional soliton with a pulse duration of 858 fs was generated using NbTe-2-based SA,which was demonstrated to be a kind of polarization-locked vector soliton in further investigation.Our experimental results reveal the nonlinear optical properties of NbTe2and broaden its applications in ultrafast photonic devices.