Recent Progress and Development Trend of Self-Sweeping Fiber Laser

Abstract

Since 2011, when Kir’yanov et al. first reported a new wavelength self-sweeping ytterbium-doped fiber laser that does not rely on any tuning element but only on the dynamic induced grating generated in the gain fiber by the standing wave resonator structure, the self-sweeping effect based on fiber waveguides has been extensively studied, leading to great progress in fundamental physics and other applications of self-sweeping fiber lasers. Different doped fiber lasers have not only achieved the self-sweeping effect, but also observed new phenomena such as anomalous self-sweeping and continuous pulses. Due to their remarkable spectral and pulsed characteristics, self-sweeping fiber lasers have been widely used in spectral detection, fiber sensing and short pulse synthesis. In this paper, we will introduce the classification of different doped self-sweeping fiber lasers, summarize their different implementations, and introduce their self-sweeping laws, pulse characteristics, recent progress of applications and future development prospects.

The diversity of operational regimes in an ytterbium-doped fiber laser with a low-Q-factor cavity

“…SLLS operation was recently observed in many FLs (see, e.g. [14] and the references therein), usually just above the laser threshold. In the present configuration, SLLS is supported within a narrow range of output powers: P out ∑ ∼0.1…0.3 W. It suddenly appears when the system starts lasing and fades when the intracavity power reaches the SBS threshold.…”

“…[3][4][5]), as in cases of 'moderate' feedback: namely, when the YDF is perpendicularly cleaved from both sides (∼3.5% Fresnel reflection), or when it is placed in a cavity with weakly reflecting couplers (usually fiber Bragg gratings (FBGs)), both resulting in coherent or quasi-coherent light generation at ∼1…1.1 µm in peculiar, somewhat uncommon, operational regimes . In particular, in CW-pumped YDFLs with a low-Q-factor cavity, self-induced laser line sweeping (SLLS) at low (up to ∼1.2 thresholds) pump powers was first observed in 2011 [6,7] and subsequently explored in many other FLs [8][9][10][11][12][13][14][15][16]. Meanwhile, at higher pump powers, irregular generation of powerful ('self-Q-switched', SQS) spikes or their bunches [3,5,[17][18][19][20][21][22] was observed, frequently characterized by unusual statistics, and referred to as 'extreme events' or 'rogue-waves' (RWs) [23][24][25][26][27][28][29][30].…”

Methods of Radiation Wavelength Tuning in Short-Pulsed Fibre Lasers

“…Sometimes, generation at different wavelengths is understood as the production of multi-wavelength radiation or output at certain discrete wavelengths, which is certainly not equivalent to continuous tuning of a single radiation pulse, even though there are cases where simultaneous tuning of several pulses may be implemented [7,8]). Neither are we considering lasers with selfsweeping of their output wavelength (wavelength-swept fibre lasers [9]), since controlling the parameters of such automatic tuning represents a separate task. We aim to identify the methods of radiation wavelength tuning in fibre lasers that produce single short (fs-ns) pulses, are free from the problems just mentioned, and provide stable (or almost unchanged) radiation parameters over the entire tuning range.…”