Self-Q-switched Ytterbium-doped all-fiber laser

Abstract

Abstract:We report an experimental realization and study of a self-Q-switched diode-pumped all-fiber Ytterbium laser. Possible mechanisms leading to establishing of self-Q-switching in the laser are discussed. Pulsed Ytterbium-doped fiber lasers operating near 1 µm are currently of increased interest as the devices potentially applicable in different areas of technology, medicine, basic research, etc. Rather than mode-locked Ytterbium fiber lasers generating ultra-short pulses (of femto-or pico-second duration), Q-switched Ytterbium fiber lasers oscillate normally pulses of nano-or submicrosecond duration ("giant pulses"). Usually the giant-pulse regimes can be realized in Ytterbium fiber lasers applying the Q-switching techniques conventional for bulk lasers, using as Q-switches acousto-or electro-optical elements, or solid-state saturable absorbers [1][2][3][4][5]. Apparently, the integrated fiber-bulk architecture of such laser schemes is a disadvantage in majority of applications. That is why implementation of Q-switched all-fiber Ytterbium lasers generating stable and powerful short pulses becomes an important point of current researches. To date, only a couple of actively Q-switched all-fiber Ytterbium laser designs have been proposed [6,7]. Meanwhile, the Q-switching arrangements in these lasers are complicate and expensive: As in all actively Q-switched lasers, additional electronic and optical circuits are needed to be incorporated in a laser scheme. So, more attention is paid now to develop passively Q-switched Ytterbium all-fiber lasers as an alternative to the actively Q-switched ones. The passive Qswitching methods to realize such lasers [8][9][10][11] have obvious potential advantages -the simplicity of implementation, low cost, and insensitivity to the environmental influences. However, there are also very few designs for passively Q-switched all-fiber Ytterbium lasers. Virtually in all these lasers the Brillouin or Raman scattering are exploited as the switching mechanisms [8][9][10]. The main drawback of the mentioned lasers is their quite instable operation that seems to stem from the stochastic nature of the Q-switching nonlinear scatterings, while giant pulses generated are quite short (nanoseconds) and powerful. An-

Narrow-linewidth Q-switched DBR laser on Ytterbium-doped glass

“…Inside those trains, pulses of 170 ns duration and around 30 kHz repetition rate can be measured. This unstable behavior has already been reported in the literature for similar devices [13], [14]. A possible cause for this self-pulsing operation can be the existence of a small re-injection of the laser signal in the cavity, coming from the multiplexer or from the output connector.…”

A Research Paper on the Performance Analysis of a Self-Mode Locking High Power Linearly Polarised Fiber Laser

“…In SML, the laser signal modulation period corresponds to the cavity round-trip time. Various mechanisms may cause self-pulsing in fiber lasers [28] including ion-pairing [29], re-absorption of laser photons in un-pumped part of fiber [30], scattering processes such as SBS or SRS [31] and Kerr effect [32]. In References [29][30][31][32], self pulsing were investigated only experimentally without numerical verification.…”

Self Q-switching of a bismuth doped silica fiber operating at 1.46 μm

“…Other method, self Q-switched fiber laser based on ytterbium [8], erbium [9], holmium doped active fibers [10], have been demonstrated.…”