Increasing mode instability thresholds of fiber amplifiers by gain saturation
Arlee V. Smith,Jesse J. Smith +1 more
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It is demonstrated that when suppression of stimulated Brillouin scattering and the population saturation effect are both taken into account, counter-pumped amplifiers have higher mode instability thresholds than co-pumping amplifiers for fully Yb3+ doped cores, and confined doping can further raise the thresholds.Abstract:
We show by numerical modeling that saturation of the population inversion reduces the stimulated thermal Rayleigh gain relative to the laser gain in large mode area fiber amplifiers. We show how to exploit this effect to raise mode instability thresholds by a substantial factor. We also demonstrate that when suppression of stimulated Brillouin scattering and the population saturation effect are both taken into account, counter-pumped amplifiers have higher mode instability thresholds than co-pumped amplifiers for fully Yb3+ doped cores, and confined doping can further raise the thresholds.read more
Citations
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High Power Fiber Lasers: A Review
TL;DR: In this article, the fundamental properties and latest developments in high-power fiber lasers are summarized and reviewed, focusing primarily on the most common fiber laser configurations and the associated cladding pumping issues.
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High-power fibre lasers
Cesar Jauregui,Jens Limpert,Jens Limpert,Jens Limpert,Andreas Tünnermann,Andreas Tünnermann,Andreas Tünnermann +6 more
TL;DR: An overview of the state of the art in the field can be found in this paper, where the authors discuss present challenges and the future outlook of high-power fiber laser applications.
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Modal instability-suppressing, single-frequency photonic crystal fiber amplifier with 811 W output power
TL;DR: An acoustic- and gain-tailored Yb-doped polarization-maintaining photonic crystal fiber is used to demonstrate 811 W single-frequency output power with near diffraction-limited beam quality, which represents the highest power ever reported from a near diffractions-limited single- frequencies fiber laser.
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Impact of photodarkening on the mode instability threshold.
TL;DR: It is experimentally shown that the highest mode instabilities threshold is reached around 1030 nm and not for the smallest wavelength separation between pump and signal, which implies that the quantum defect is not the only source of thermal heating in the fiber.
Journal ArticleDOI
Transverse mode instability
TL;DR: In this paper, the authors present a review on the effect of transverse mode instability in high-power fiber laser systems and the corresponding investigations led worldwide over the past decade, including a description of the experimental observations and the physical origin of this effect.
References
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Journal ArticleDOI
Tensile strain dependence of Brillouin frequency shift in silica optical fibers
TL;DR: In this paper, the authors measured the Brillouin frequency shift in a single-mode optical fiber as a function of tensile strain and found that the strain coefficient was 4.4 for silica fibers.
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Mode instability in high power fiber amplifiers
Arlee V. Smith,Jesse J. Smith +1 more
TL;DR: For powers exceeding a sharp threshold in the vicinity of several hundred watts the beam quality from some narrow bandwidth fiber amplifiers is severely degraded, and it is shown that this can be caused by transverse thermal gradients induced by the amplification process.
Journal ArticleDOI
Origin of thermal modal instabilities in large mode area fiber amplifiers.
TL;DR: A dynamic model of thermal modal instability in large mode area fiber amplifiers allowing the pump and signal optical intensity distributions to apply a time-varying heat load distribution within the fiber is presented.
Journal ArticleDOI
Stimulated thermal Rayleigh scattering in optical fibers.
TL;DR: In this work, a quasi-closed-form solution for the nonlinear coupling coefficient is found for stimulated thermal Rayleigh scattering in optical fibers, which helps to significantly improve understanding of mode instability.
Journal ArticleDOI
Al/Ge co-doped large mode area fiber with high SBS threshold.
Ming-Jun Li,Xin Chen,Ji Wang,Stuart Gray,Anping Liu,Jeffrey Demeritt,A.B. Ruffin,Alana M. Crowley,Donnell T. Walton,Luis A. Zenteno +9 more
TL;DR: A novel approach of making large effective area laser fiber with higher threshold for the stimulated Brillouin scattering (SBS) using Al/Ge co-doping in the fiber core using an Yb-doped double clad fiber fabricated by the OVD process.