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Large optical nonlinearity at short‐wavelength‐infrared (SWIR) has enabled 2D MXene to be used explosively in ultrafast nonlinear photonics and optoelectronics. Despite the high technological interest in V4C3 MXene in electrochemistry, investigations from a nonlinear photonics perspective have yet to be conducted. Here, the nonlinear optical characteristics of V4C3 MXene at SWIR wavelengths are systemically investigated. First, Z‐scan measurements are performed and the saturated absorption and self‐defocusing properties of V4C3 MXene at both wavelengths of 1560 and 1910 nm are observed. Density functional theory calculation shows metallic characteristics of V4C3 MXene. Based on the saturable absorption properties of V4C3 MXene, a single saturable absorber (SA) operating at both wavelengths of 1560 and 1910 nm is experimentally implemented. Stable mode‐locked pulses of 638 fs pulse duration at 1559.9 nm are produced instantaneously from an erbium‐doped fiber ring cavity using SA. The same SA generates 1.08 ps mode‐locked pulses at 1911.9 nm from the thulium holmium co‐doped fiber ring cavity. This indicates that the operating bandwidth of this realized V4C3 MXene‐based SA could be at least 350 nm. This work strongly suggests that V4C3 MXene can serve as an ultra‐broadband and high‐performance nonlinear optical material platform in the SWIR regions.

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This review summarizes recent developments of saturable absorbers (SAs) based on 2D materials for nonlinear optical absorption and ultrafast pulsed laser generation. Apart from graphene, various 2D materials such as topological insulators and transition metal dichalcogenides are investigated for SA applications and their important potential as passive mode-lockers for femtosecond laser production are extensively investigated. By selecting appropriate 2D materials, a wide spectral range of passively mode-locked pulsed lasers are obtained, covering visible, midinfrared and a terahertz region. A set of different approaches is used for fabricating SA modules of fiber laser photonics, which include sandwiching, side-polishing and tapering methods. Noticeably, through systematic studies, it is demonstrated that layer-stacking seldom deteriorates the SA performance of 2D materials in the evanescent regime, although their ultrathin nature may improve the efficiency in a transmission mode like sandwich-type SAs. The direction for designing new SAs is presented based on material characterization.

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