We demonstrate an erbium-doped fiber laser passively mode-locked by a multilayer molybdenum disulfide (MoS₂) saturable absorber (SA). The multilayer MoS₂ is prepared by the chemical vapor deposition (CVD) method and transferred onto the end-face of a fiber connector. Taking advantage of the excellent saturable absorption of the fabricated MoS₂-based SA, stable mode locking is obtained at a pump threshold of 31 mW. Resultant output soliton pulses have central wavelength, spectral width, pulse duration, and repetition rate of 1568.9 nm, 2.6 nm, 1.28 ps, and 8.288 MHz, respectively. The experimental results show that multilayer MoS₂ is a promising material for ultrafast laser systems.

We report an erbium-doped fiber laser passively Q-switched by a few-layer molybdenum disulfide (${\mathrm{MoS}}_2$) saturable absorber (SA). The few-layer ${\mathrm{MoS}}_2$ is grown by the chemical vapor deposition method and transferred onto the end-face of a fiber connector to form a fiber-compatible ${\mathrm{MoS}}_2$ SA. The laser cavity is constructed by using a three-port optical circulator and a fiber Bragg grating (FBG) as the two end-mirrors. Stable Q-switched pulses are obtained with a pulse duration of 1.92 μs at 1560.5 nm. By increasing the pump power from 42 to 204 mW, the pulse repetition rate can be widely changed from 28.6 to 114.8 kHz. Passive Q-switching operations with discrete lasing wavelengths ranging from 1529.8 to 1570.1 nm are also investigated by using FBGs with different central wavelengths. This work demonstrates that few-layer ${\mathrm{MoS}}_2$ can serve as a promising SA for wideband-tunable Q-switching laser operation.

Graphene/WS₂ (G/WS₂) van der Waals (vdW) heterostructures are utilized as saturable absorbers (SAs) in compact mode-locked fiber lasers operating in the telecommunication L-band for the first time. The interlayer coupling is confirmed by Raman and photoluminescence spectra. In comparison with pure WS₂, the heterostructure exhibits excellent nonlinear optical properties in terms of larger modulation depth and lower saturation intensity due to the strong interlayer coupling. By incorporating the G/WS₂-based SA into an all-anomalous-dispersion fiber laser, stable conventional-soliton pulses with a pulse duration down to 660 fs can be realized at 1601.9 nm, manifesting better output performance compared to pure WS₂. In addition, through shifting the cavity dispersion to the net-normal dispersion, the G/WS₂ SA can also be applied for dissipative-soliton generation. Resultant output pulses feature the central wavelength of 1593.5 nm and the pulse duration of 55.6 ps. Our results indicate that the G/WS₂ vdW heterostructure is a promising candidate as SA for pulsed laser applications, which pave the way for the development of novel ultrafast photonic devices with desirable performance.

We report on supercontinuum generation in a highly nonlinear fiber (HNLF) pumped by noise-like pulses (NLPs) emitted from a compact fiber ring laser. The compact erbium-doped fiber ring laser is constructed by using an optical integrated component and mode-locked by the nonlinear polarization rotation technique. The laser produces NLPs with a 3-dB spectral bandwidth of 60.2 nm, repetition rate of 9.36 MHz, and pulse energy of 2.8 nJ. Numerical simulations reproduce the generation of NLPs in the experiment. The NLPs are then launched into a 110-m-long HNLF and a supercontinuum with a 20-dB spectral width over 500 nm is obtained. Such a simple and inexpensive supercontinuum-generation system is a potential alternative for various practical applications.

Generation of dissipative soliton resonance (DSR) is numerically investigated in an all-normal-dispersion Yb-doped fiber laser mode-locked by a real saturable absorber (SA). In the simulation model, the SA includes both the saturable absorption and reverse saturable absorption (RSA) effects. It is found that the RSA effect induced by the SA material itself plays a dominant role in generating the DSR pulses. We also systematically analyze the influence of key SA parameters on the evolution of DSR pulses in the cavity. Our simulation results not only offer insight into the underlying mechanism of DSR generation in mode-locked fiber lasers by means of real SAs, but also provide a guideline for engineering SA parameters to generate optical pulses with the highest possible energy.

We present a comprehensive numerical investigation of the polarization dynamics of dissipative-soliton-resonance (DSR) pulses in a passively mode-locked Yb-doped fiber laser with a nonlinear optical loop mirror (NOLM). In our simulations, the NOLM’s saturable absorption effect is modeled by its transmission function. Depending on the strength of cavity birefringence, various types of vector DSR pulses, including the polarization-locked DSR (PL-DSR), the polarization rotation-locked DSR (PRL-DSR), and the group velocity-locked DSR (GVL-DSR) states are obtained in the laser cavity. The characteristics of these vector DSR pulses are shown. We also analyze the polarization evolution and internal polarization dynamics of PRL-DSR pulses within the cavity. Our simulation results offer insight into the vector nature of DSR pulses in polarization-insensitive mode-locked fiber lasers.