Large-energy mode-locked ytterbium-doped linear-cavity fiber laser based on chemical vapor deposition-Bi2Se3 as a saturable absorber

Layer-dependent nonlinear optical properties of two-dimensional InSe and its applications in waveguide lasers

The thickness-dependent third-order nonlinear optical properties of two-dimensional β-InSe and its potential applications as a saturable absorber in pulsed laser generation are investigated. InSe sheets with different layers are prepared by the chemical vapor deposition. Using open-aperture femtosecond Z-scan technique at 1030 nm, the modulation depth and nonlinear absorption coefficient are obtained to be 36% and -1.6 × 10⁴ cm·GW^-1, respectively. The intrinsic mechanism of the layer-dependent energy band structure evolution is analyzed based on density functional theory, and the theoretical analysis is consistent with the experimental results. Based on a waveguide cavity, a Q-switched mode-locked laser at 1 µm with a repetition frequency of 8.51 GHz and a pulse duration of 28 ps is achieved by utilizing the layered InSe as a saturable absorber. This work provides an in-depth understanding of layer-dependent properties of InSe and extends its applications in laser technology for compact light devices.

Mode-Locked YDFL Using Topological Insulator Bismuth Selenide Nanosheets as the Saturable Absorber

Fiber lasers have long remained relevant for various applications worldwide in many industries. This paper presents a mode-locked ytterbium-doped fiber laser (YDFL) using our home-made topological insulator Bi2Se3 nanosheets (TI Bi2Se3) as the saturable absorber. The fabricated TI Bi2Se3 is transported to the end of the fiber ferrule using an optical deposition process, which is a key ingredient for initiating a pulsed fiber laser. With a pump power of 211.1 mW, the captured repetition rate and pulse width are 8.3 MHz and 6.2 ns, respectively. The length of the setup configuration is approximately 20 m, which corresponds to an output power measurement of 12.4 mW with a calculated pulse energy of 1.5 nJ. There are no significant Kelly sidebands, but the strong stability of the pulsed laser is defined by a high signal-to-noise ratio (SNR) of around 60.35 dB.

All-normal-dispersion dissipative soliton fiber laser using an offset-splicing graded-index-multimode-fiber-based saturable absorber

All-normal-dispersion (ANDi) dissipative soliton mode-locking is realized based on nonlinear multimode interference (NMI), which is implemented by offset-splicing three pieces of graded-index multimode fibers (GIMFs) and acts as a saturable absorber. The higher-order modes can be excited by offset-splicing GIMFs (OS-GIMFs), which eliminates adding the step multimode fiber (SIMF) into the resonant cavity and the precise length requirement of the SIMF. In the experiment, the stable dissipative soliton mode-locking at 1030 nm can be obtained with the pulse width of 7.3 ps and the repetition rate of 20.52 MHz, and the bandwidth is 6.98 nm. The maximum output is 3.2 mW with the pump power of 257 mW. The OS-GIMFs can significantly improve the saturated absorption and can easily realize dissipative soliton mode-locking in ANDi regions, which makes it attractive in ultrafast photonics.