Power scalability in high power fiber amplifiers
Power scalability in high power fiber amplifiers
High power fiber lasers (HPFLs) have shown record single-moded diffraction-limited output powers in the range of 20kW [1]. Output power limits are known to be set by the launched pump power, nonlinear effects (such as stimulated Raman (SRS) or Brillouin (SBS) scattering), optical damage, glass rapture or melting, and thermal lensing (TL) [2]. More recently, transverse mode instability (TMI) is identified as an additional severely power limiting effect [3] and a simple threshold formula was derived [4]. Although TL and TMI are both of thermal origin and show the same functional dependence on (λ0/d0)2 , where λ0 is the signal wavelength and d0 the core diameter [2, 4], TMI can be detrimental for the output beam quality, while TL results in shrinkage of the initial (“cold”) mode field diameter (MFD) ω0 [2] and therefore limits the output power scalability indirectly (e.g. by reducing the nonlinear thresholds). The TL power threshold has been set arbitrarily to the level that results in ω0TL ≈ Q.7 - Q.8ω0 [2], and therefore its impact on power scalability is somewhat artificial.
Zervas, Michalis N.
1840a474-dd50-4a55-ab74-6f086aa3f701
2017
Zervas, Michalis N.
1840a474-dd50-4a55-ab74-6f086aa3f701
Zervas, Michalis N.
(2017)
Power scalability in high power fiber amplifiers.
2017 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC), , Munich, Germany.
25 - 29 Jun 2017.
(doi:10.1109/CLEOE-EQEC.2017.8087024).
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Conference or Workshop Item
(Paper)
Abstract
High power fiber lasers (HPFLs) have shown record single-moded diffraction-limited output powers in the range of 20kW [1]. Output power limits are known to be set by the launched pump power, nonlinear effects (such as stimulated Raman (SRS) or Brillouin (SBS) scattering), optical damage, glass rapture or melting, and thermal lensing (TL) [2]. More recently, transverse mode instability (TMI) is identified as an additional severely power limiting effect [3] and a simple threshold formula was derived [4]. Although TL and TMI are both of thermal origin and show the same functional dependence on (λ0/d0)2 , where λ0 is the signal wavelength and d0 the core diameter [2, 4], TMI can be detrimental for the output beam quality, while TL results in shrinkage of the initial (“cold”) mode field diameter (MFD) ω0 [2] and therefore limits the output power scalability indirectly (e.g. by reducing the nonlinear thresholds). The TL power threshold has been set arbitrarily to the level that results in ω0TL ≈ Q.7 - Q.8ω0 [2], and therefore its impact on power scalability is somewhat artificial.
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Published date: 2017
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2017 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC), , Munich, Germany, 2017-06-25 - 2017-06-29
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Local EPrints ID: 442320
URI: http://eprints.soton.ac.uk/id/eprint/442320
PURE UUID: 94c4d8a8-fc87-499b-89b3-b9bf0656ccdb
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Date deposited: 13 Jul 2020 16:31
Last modified: 17 Mar 2024 02:37
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