High-power passively Q-switched thulium fiber laser with distributed stimulated Brillouin scattering

Abstract

We report a novel passively Q-switched 2 μm Tm(3+) fiber laser simply by distributed stimulated Brillouin scattering with an all-fiber configuration. The maximum output power is 2.49 W with an optical-to-optical slope efficiency of 12%, and the laser wavelength is centered at ~1991 nm with a spectral width of >10 nm. The single pulse energy can be over 50 μJ with a pulse width of about 20 ns, and the pulse repetition rate can be tuned from several kilohertz to tens of kilohertz by changing the pump power. To the best of our knowledge, this is the highest-average-power passively Q-switched 2 μm Tm(3+) fiber laser in the nanosecond regime.

Recent advances in fundamentals and applications of random fiber lasers

“…Similar passive Q switching was also observed in other experiments [110,111], and was explained as an instability effect arising from the second cascade of the SBS [110]. More recently, Rayleigh mediated Q switching was obtained in a thulium-based system, giving rise to 20 ns, 50 mJ pulses in the 2 μm wavelength region [112].…”

55 W actively Q-switched single oscillator Tm3+, Ho3+-codoped silica polarization maintaining 209 µm fiber laser

“…Passive modulation methods have been mostly used in the literature using saturable absorbers. Passive Q-switching using saturable absorbers based on semiconductor saturable-absorber mirrors (SESAMs) [7,8], graphene layer [9], distributed stimulated Brillouin scattering nonlinear effect [10,11], antiresonant Fabry-Perot [12] and nonlinear polarization evolution [13] have been demonstrated. The output power and pulse energy in passive modulation techniques from single oscillators are limited, on one hand, to a certain output power level for stable operation, and on the other hand, by the damage threshold of the available modulators.…”

Pulse duration tunable fiber CPA system based on thermally dispersion tuning of chirped fiber bragg grating

“…However, the extraction of ultra-short laser pulses possessing high peak power from fiber laser system is significantly more challenging than in bulk laser systems due to the high intensities in the fiber core sustained over considerable interaction length, which evoke nonlinear pulse distortions, mainly by self-phase modulation (SPM) [2]. In order to avoid nonlinear effects [3] during pulse amplification, the common approach is to enlarge the mode-field diameter of the fiber and temporal stretching of the pulse so as to reduce the peak power [4].…”