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We report a simple and compact design of a dispersion compensated mode-locked Yb:fiber oscillator based on a nonlinear amplifying loop mirror (NALM). The fully polarization maintaining (PM) fiber integrated laser features a chirped fiber Bragg grating (CFBG) for dispersion compensation and a fiber integrated compact non-reciprocal phase bias device, which is alignment-free. The main design parameters were determined by numerically simulating the pulse evolution in the oscillator and by analyzing their impact on the laser performance. Experimentally, we achieved an 88 fs compressed pulse duration with sub-fs timing jitter at 54 MHz repetition rate and 51 mW of output power with 5.5 × 10−5 [20 Hz, 1 MHz] integrated relative intensity noise (RIN). Furthermore, we demonstrate tight phase-locking of the laser's carrier-envelope offset frequency (ƒceo) to a stable radio frequency (RF) reference and of one frequency comb tooth to a stable optical reference at 291 THz. [ABSTRACT FROM AUTHOR]

Since graphene was first reported as a saturable absorber to achieve ultrafast pulses in fiber lasers, many other two-dimensional (2D) materials, such as topological insulators, transition metal dichalcogenides, black phosphorus, and MXenes, have been widely investigated in fiber lasers due to their broadband operation, ultrafast recovery time, and controllable modulation depth. Recently, solution-processing methods for the fabrication of 2D materials have attracted considerable interest due to their advantages of low cost, easy fabrication, and scalability. Here, we review the various solution-processed methods for the preparation of different 2D materials. Then, the applications and performance of solution-processing-based 2D materials in fiber lasers are discussed. Finally, a perspective of the solution-processed methods and 2D material-based saturable absorbers are presented. [ABSTRACT FROM AUTHOR]

We demonstrate a compact 29.3 GHz visible astro-comb covering the spectrum from 560 nm to 700 nm. A 837 MHz Yb:fiber laser frequency comb phase locked to a Rb clock served as the seed comb to ensure the frequency stability and high side mode suppression ratio. After the visible super-continuum generation, a Fabry-Perot cavity based on ultra-low expansion glass was utilized to filter the comb teeth. The mirrors were home-made complementary chirped mirrors pair with zero net-dispersion and high reflection to guarantee no mode skipping. Those filtered comb teeth were clearly resolved in an astronomical spectrograph of 49 000 resolution, exhibiting sharp line shape, zero noise floor, and uniform exposure amplitude. [ABSTRACT FROM AUTHOR]

• Reverse saturable absorption effect of real saturable absorber on conventional and dissipative solitons is investigated. • Reverse saturable absorption effect clamps peak power of conventional and dissipative solitons. • Revealing the role of reverse saturable absorption effect in different mode-locked regimes. We numerically investigate the influence of the reverse saturable absorption effect of real saturable absorbers on conventional and dissipative solitons. The results show that the reverse saturable absorption effect leads to more loss and clamps peak power of both conventional and dissipative solitons, but plays different roles on their properties. When the cavity operates at conventional solitons state, the reverse saturable absorption effect restricts the maximum pulse energy to less than 0.1 nJ, facilitates the formation of multiple solitons, but maintains the time-bandwidth product close to 0.315, indicating the pulses maintain the sech2 shape. While the cavity operates at dissipative solitons state, the reverse saturable absorption effect increases the maximum pulse energy from 11 to 13 nJ and plays a key role in transforming the pulse states, which further facilitates the generation of dissipative soliton resonance pulses. In addition, the reason of the different influences on pulses in two mode-locked regimes is also discussed. Our results reveal the role and promote the rational use of the reverse saturable absorption effect in different mode-locked regimes. [ABSTRACT FROM AUTHOR]