21 kW, 166 fs pulses from passive mode-locked ytterbium-doped fiber laser employing Bi2O2Te nanosheets as saturable absorber in 1 μm.

Ultrafast pulsed lasers are pivotal in advanced domains such as optical communications, optical metrology, all-optical sampling, optical frequency combs, laser ranging, and laser machining, where saturable absorbers (SAs) are crucial components. Various SAs based on two-dimensional (2D) materials have attracted great attention in recent years due to their low cost, high stability, large modulation depth, broadband absorption, and excellent optical nonlinearity. In this work, Bi2O2Te nanosheets (NSs) based SA with a saturation intensity of 20.6 MW/cm2 and a modulation depth of 2.2% was prepared by utilizing liquid phase exfoliation (LPE) technique, which was firstly applied to a passively mode-locked ytterbium-doped fiber laser (YDFL). The experiment results show that a sequence of dissipative soliton (DS) pulse train with a repetition frequency of 3.303 MHz was obtained at 1032.5 nm. The pulse duration, signal-to-noise ratio (SNR), and maximum peak power were 166 fs, 70 dB, 21 kW, respectively. The results not only underscore the potential of Bi2O2Te NSs-based SA for ultrafast photonics applications around 1 μm wavelength, but also open a way for further exploration of high-performance, all-fiber laser sources utilizing 2D materials. [ABSTRACT FROM AUTHOR]