A multiple soliton state erbium-doped fiber laser based on a MoS2/C saturable absorber

Transition metal dihalide (TMD) heterojunction materials possess distinct advantages in the field of optoelectronics, which has resulted in their extensive research in recent years. In this work, MoS₂/C heterojunctions were synthesized using a hydrothermal method and deposited onto a tapered fiber with a diameter of 10.93 μm to form saturable absorbers (SAs) using photodeposition. The integration of MoS₂/C SA into an erbium-doped fiber laser (EDFL) enabled the realization of multiple stable and switchable mode-locking states under different dispersion conditions, including conventional solitons, bound-state solitons, and higher-order harmonic mode-locking. Among them, conventional solitons could be realised in the range of dispersion from −0.303 ps² to −1.18 ps², with the narrowest pulse width reaching up to 856 fs. Double-soliton bound states up to four-soliton bound states could be realized at a dispersion of −0.303 ps². At a dispersion value of −0.734 ps², a variety of higher-order harmonics could be achieved, with up to 88th harmonic mode-locking exhibiting a frequency of 499.7 MHz. These results demonstrate that MoS₂/C exhibits excellent nonlinear optical modulation properties and holds promise as a broadband nonlinear optical material.