Extreme energy pulsed fiber lasers

M. Y. Chen, Yu-Chung Chang, P. Mamidipudi, R. Changkakoti, D. Engin, A. Galvanauskas

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Citation (Scopus)


Recently demonstrated kW-level average powers in diffraction-limited beams from fiber lasers have established fiber technology as, perhaps, the most powerful solid-state laser technology1,2,3,4. Pulsed energy scaling, however, is significantly more difficult frontier for fiber lasers, due to limited mode area and relatively long signal-propagation lengths. We experimentally explored high energy and high peak power pulse generation in very large core multimode fiber amplifiers, achieving the highest ever reported energies of up to 82-mJ for 500-ns pulses, of up to 27-mJ for 50-ns pulses, and of up to 2.4-M W peak power for 4-ns long pulses at 1064 nm5. Fiber core sizes used in these studies ranged from 50-μm up to 200-μm, just above the single-transverse mode operation achievable with low-NA fibers with core diameters of up to ∼50-μm. Highly multimode nature of these very large core fibers was mitigated by using coiling-induced mode-filtering effect. For example, with 200-μm core fiber we demonstrated output-beam quality improvement from M2=25 from an uncoiled fiber to M2=6.5 from a properly coiled fiber, with the corresponding reduction in a number of propagating transverse modes from ≥ 200 to ≤ 20. Use of such large-core fibers allows avoiding energy and peak power limitations by Stimulated Raman Scattering. However, the achieved pulse energies are approaching fundamental limits set by bulk-damage and self-focusing effects. Note, that bulk-damage threshold peak-power is proportional to fiber mode (or core) area and, therefore, can be increased by resorting to larger core sizes. Self-focusing threshold is determined by the critical self-focusing peak power in a fiber glass (Pcr = 3.7 M W in fused silica) irrespective of the core size (and pulse duration) and, therefore, determines ultimate limits in achievable peak powers in single-fiber lasers and amplifiers. Such high peak-power and pulse energy fiber lasers are finding increasing use in a broad variety of applications. Pulsed material processing systems should greatly benefit from increased average powers of fiber lasers. Remote sensing applications require compactness and efficiency of fiber laser sources. And recent demonstration of generating EUV radiation with a pulsed fiber laser [6] opens a new technological pathway towards laser-based 13.5-nm EUV lithography sources.

Original languageEnglish
Title of host publication2005 Conference on Lasers and Electro-Optics Europe
Publication statusPublished - 2005 Dec 1
Event2005 Conference on Lasers and Elctro-Optics Europe - Munich, Germany
Duration: 2005 Jun 122005 Jun 17


Other2005 Conference on Lasers and Elctro-Optics Europe

All Science Journal Classification (ASJC) codes

  • Control and Systems Engineering
  • Electrical and Electronic Engineering

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