Due to the unique properties of two‐dimensional (2D) materials, much attention has been paid to the exploration and application of 2D materials. In this review, we focus on the application of 2D materials in mode‐locked fiber lasers. We summarize the synthesis methods for 2D materials, fiber integration with 2D materials and 2D materials based saturable absorbers. We discuss the performance of the diverse mode‐locked fiber lasers in the typical operating wavelength such as 1, 1.5, 2 and 3 μm. Finally, a summary and outlook of the further applications of the new materials in mode‐locked fiber lasers are presented.

We demonstrate, to the best of our knowledge, the first double-pass pre-chirp managed fiber amplifier. The double-pass fiber amplifier exhibits high gain allowing us to amplify chirped picosecond pulses from 20 mW to 113 W in a rod-type Yb-fiber corresponding to 38 dB gain. We study the dependence of static mode degradation (SMD) on the nonlinear phase shift (NPS) accumulated by the amplified pulse. Our results indicate that a larger nonlinear phase shift results in stronger nonlinear polarization evolution of the fundamental mode and leads to a lower threshold for SMD. After optimization, our pre-chirp managed amplifier seeded by 80 mW pulses delivers 102 W amplified power from the main output. The amplified pulses are compressed to 37 (55) fs with 90 (100) W average power by a grating pair (chirped mirrors). The double-pass configuration significantly simplifies the implementation of pre-chirp managed fiber amplifiers leading to an extremely compact system.

In this article, a high‐quality saturable absorber (SA) based on a two‐dimensional ternary chalcogenide Ta ₂ NiS ₅ nanosheet has been successfully fabricated and used in 1‐ and 1.5‐μm spectral regions to generate ultrafast laser pulses. The Ta ₂ NiS ₅ ‐based SA is fabricated by mechanical exfoliation and sandwiched between two fiber ferrules to form a fiber‐compatible SA. On the basis of the twin‐detector technique, nonlinear optical absorption of the Ta ₂ NiS ₅ ‐SA is characterized by 64.7% and 11.95% modulation depths with 1.3 and 0.72 MW/cm ² saturation intensities at 1028 and 1570 nm, respectively. When Ta ₂ NiS ₅ ‐SA is integrated into Yb‐ and Er‐doped fiber laser cavities, stable self‐starting Q‐switched pulses are observed. Furthermore, by adjusting the cavity structure and optimizing dispersion in the cavity, we obtain hybrid mode‐locking and mode‐locking fiber laser operation at 1029 and 1569 nm, respectively. These results validate the performance of Ta ₂ NiS ₅ as a broadband SA for the generation of ultrafast laser pulses, offering new opportunities of ternary transition‐metal dichalcogenide alloys in future photonic devices.

We report $Q$-switched and mode-locked erbium-doped all-fiber lasers using ternary ${\mathrm{ReS}}_{2(1-x)}{\mathrm{Se}}_{2x}$ as saturable absorbers (SAs). The modulation depth and saturable intensity of the film SA are 1.8% and $0.046\mathrm{MW}/{\mathrm{cm}}^2$. In $Q$-switched mechanism output, the pulse was centered at 1531.1 nm with maximum pulse energy and minimum pulse width of 28.29 nJ and 1.07 μs, respectively. In mode-locked operation, the pulse was centered at 1561.15 nm with pulse width of 888 fs, repetition rate of 2.95 MHz, and maximum pulse energy of 0.275 nJ. To the best of our knowledge, this is the first report on the mode-locked ${\mathrm{Er}}^{3+}$-doped fiber laser using ternary transition metal dichalcogenides. This work suggests prospective 2D-material SAs can be widely used in versatile fields due to their attractive optoelectronic and tunable energy bandgap properties.

We report two kinds of Q-switched Yb-doped fiber lasers based on black phosphorus saturable absorber (BP-SA). The BP-SAs are prepared by two different methods, one of which is the mechanical exfoliation method and the other is the liquid phase exfoliation method. The BP-SAs are inserted into the all-fiber Yb-doped oscillation cavity in different forms. We have experimentally shown that the passively Q-switched pulse trains could be obtained in the two methods. Firstly, we achieve the Q-switched pulse in the 1029.63 nm by using few layers black phosphorus sheet .The fiber laser was capable of generating pulses with a maximum average output power and repetition rate of 13.12 mW and 79.46 KHz, respectively, corresponding to the maximum single pulse energy of 165.11 nJ and the shortest single pulse width of 1.55's. In addition, we obtain narrower pulse width by dropping the black phosphorus solution onto the tapered fiber. The maximum single pulse energy of 114.72 nJ, and the minimum pulse width of 1.09 7mu;s was obtained, respectively. The repetition rate range is from 49.13 kHz to101.3 kHz.

We incorporate two techniques into pre-chirp managed amplification (PCMA) to achieve high-energy ultrashort pulses with the duration well below 100 fs. Numerical simulations confirmed by our experimental results demonstrate that seeding PCMA with circularly polarized pulses instead of linearly polarized pulses can increase the amplified pulse energy by 1.5 times. We also employ high-dispersion chirped mirrors to compress the amplified pulses with the throughput efficiency as high as 98%. These two techniques allow us to demonstrate an Yb-fiber PCMA system that emits 50-MHz, 47-fs pulses with 101.2-W average power.