  Niobium telluride (NbTe$_2$), 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 NbTe$_2$ in ultrafast photonics have been reported. In this
work, a NbTe$_2$-based saturable absorber (SA) was applied in an erbium-doped
fiber as a mode-locked device, and a vector soliton based on NbTe$_2$ was
obtained for the first time. NbTe$_2$-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 NbTe$_2$-based SA film
tested through the open-aperture Z-scan laser measurement is 0.62. 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 NbTe$_2$ and broaden its applications in
ultrafast photonic devices.
