An experimental analysis of self-Q-switching via stimulated Brillouin scattering in an ytterbium doped fiber laser

Abstract

An experimental study of self-Q-switching (SQS) in an ytterbium doped fiber laser (YDFL) arranged using a twin-core GTWave assembly is reported. The main mechanisms that initiate, amplify, and limit SQS pulses in amplitude are revealed to be stimulated Brillouin and Raman scattering (SBS/SRS) and Yb3+ amplified spontaneous emission. The parameters featuring SQS oscillation in terms of efficiency and stability of pulsing are found to be intra-cavity loss and feedback strength. An analysis of the YDFL SQS regime’s features—pulsing time series, optical and RF spectra, amplitude and timing jitter—is provided for the two experimental situations: (i) when SQS pulsing stochastically intermits with regular active Q-switching pulses, given by the action of an intra-cavity acousto-optical modulator, and (ii) when a pure SQS mode is intentionally implemented in the YDFL without a modulator. The close relationship of the processes involved and SQS parameters in these two circumstances is demonstrated. Giant pulses with durations of 70–80 ns are shown to be generated at threshold intra-cavity powers of around 250 W (SBS threshold) and limited at approximately 2 kW of peak power (SRS threshold). At SBS-SQS, we show that at high values of intra-cavity loss, and thus reduced feedback, the amplitude and timing jitter values can be reduced to 5% and 7%, respectively.

Recent progress on optical rogue waves in fiber lasers: status, challenges, and perspectives

“…When the fiber lasers are mode locked by the 2-D materials, these materials can not only provide excellent saturable absorption properties but also enhance the nonlinear effects for the pulse interactions in the fiber lasers, which benefits the formation of RWs. Different from the MLFL, the SBS effects can be formed in the Qswitched random lasers 125 and the self-pulsing fiber lasers. 127 The influence of SBS can introduce a trigger effect for the RW generation.…”

“…Stimulated Brillouin scattering (SBS) has been recently considered as a trigger effect for the generation of RWs. Experimentally, Brillouin scattering-induced RWs in self-pulsing fiber lasers, 91 Q-switched random laser, 125 and high power amplifier 126 were reported. Boukhaoui et al numerically studied the influence of SBS on the occurrence of RWs in self-pulsing fiber lasers.…”

Ytterbium-doped fiber laser as pulsed source of narrowband amplified spontaneous emission

“…Output power of DC YDFLs is scalable from several watts to tens kW 11,12,21,22 or few hundreds kW 22–25 at single-mode and multimode operation, respectively. When cavity Q-factor of YDFL is low and thus YDF gain is high, the laser turns to the regime of random kW pulses (rogue waves), driven by stimulated Brillouin scattering 26–28 .…”

A Novel Repetition Rate Adjustable SBS-Based Q-Switched Fiber Laser

“…Taking advantage of this feature, the SBS-based Q-switched fiber laser was proposed and demonstrated. Due to its no-feedback cavity and Q-switching mechanism, SBS-based Q-switched fiber laser have many unique features in comparison with common passively Q-switched fiber lasers, such as extreme simplicity, no wavelength limit, high peak-average power ratio and random output [8]- [10]. To date, instability of SBS-based Q-switched lasers have been successfully utilized for supercontinuum generation, rough wave study and random laser [7], [11], [12].…”