1.5 μm ultrafast fiber laser with multi-soliton states based on tellurene saturable absorber

With the increasing research on two-dimensional layered elemental materials (Xenes) in recent years, their application scenarios have become increasingly diverse. For example, tellurene, as a high-performance saturable absorber, has demonstrated significant potential in passively mode-locked fiber lasers due to its tunable bandgap, particularly exhibiting excellent absorption characteristics in the near-infrared region. However, current studies on tellurene in the field of ultrafast lasers remain relatively limited. In this work, tellurene was thoroughly characterized, and a saturable absorber was fabricated based on a tapered fiber via the optical deposition method. Under different polarization states, six types of conventional soliton pulses were obtained, with the narrowest pulse width reaching 954 fs. Additionally, by increasing the pump power and adjusting the intra-cavity polarization state, harmonic mode-locking and bound-state soliton mode-locking were achieved. Experimental results demonstrate that the tellurene-based saturable absorber exhibits excellent pulse modulation capability in the 1.5 μm wavelength region and indicate that tellurene-based fiber lasers represent a promising platform for soliton dynamics research.