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SCIENCE CHINA Information Sciences, Volume 62, Issue 4: 041301(2019) https://doi.org/10.1007/s11432-018-9742-0

Development status of high power fiber lasers and their coherent beam combination$^\dag$

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  • ReceivedMay 11, 2018
  • AcceptedDec 7, 2018
  • PublishedFeb 27, 2019

Abstract

High-power fiber laser has been emerged great potential in a wide range of applications and becomes a robust candidate for high energy solid state laser system. To further increase the output brightness of single-channel fiber laser, high-brightness pump sources and high-power-handling passive components should be fabricated and utilized in the fiber laser systems, in addition to the advanced techniques for multiple nonlinear effects managements. The state-of-the-art high power fiber lasers are reviewed, in terms of narrow-linewidth fiber lasers, broadband fiber lasers and fiber lasers at 2 $\mu$m. Coherent beam combining is a promising technique to obtain higher output power while maintaining excellent beam quality simultaneously, which breaks through the bottlenecks of single-channel fiber laser. Based on a series of key techniques for coherent beam combining, high-power coherent beam combining of fiber lasers could be enabled with high combining efficiency. In this paper, we review the progress of high-power fiber lasers and their coherent beam combining in the recent decade, particularly the relevant work in our group. The future prospects of fiber lasers and coherent beam combining technique are also discussed.


Acknowledgment

This work was supported by National Natural Science Foundation of China (Grant Nos. 61705264, 61705265). Authors would like to acknowledge Jinyong LENG, Hu XIAO, Yanxing MA, Jiangming XU, Xiaolin WANG, Zilun CHEN, Liangjin HUANG, Wei LIU, Tianyue HOU, Baolai YANG, and Zhaokai LOU in College of Advanced Interdisciplinary Studies, National University of Defense Technology for their collaboration.


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  • Figure 1

    (Color online) Typical setup of fiber laser system. (a) Laser oscillator; (b) laser amplifier.

  • Figure 2

    (Color online) Output properties of the 1018 nm fiber laser [33] © Copyright 2015 Optical Society of America. (a) Output power; (b) optical spectrum at 476 W.

  • Figure 3

    (Color online) (a) The comprehensive test platform for high power laser combiner, fiber endcap and cladding light stripper; (b) the beam quality measurement at maximal output power [58].

  • Figure 4

    (Color online) Experimental results of the 414 W single-frequency and single-polarization MOPA system [28] © Copyright 2016 Optical Society of America. (a) Dependence of the output power and backward power on the coupled pump power; (b) dependence of the polarization degree on the output power; (c) temporal trace of the laser at the maximum output power and the corresponding Fourier transform spectrum (the inset is the beam profile at the maximum output power).

  • Figure 5

    (Color online) Experimental results of the narrow-linewidth near-diffraction-limited all-fiber PM amplifier [73] © Copyright 2017 Astro Ltd. Reproduced by permission of IOP Publishing. (a) The output power scaling process along with increase of pump power (inset shows the beam profile at 2.43 kW); (b) the spectral distributions at 17 W and 2.43 kW; (c) the measured PER result with increase of output power.

  • Figure 6

    (Color online) Experimental results of the 4 kW-level narrow-linewidth fiber laser system. (a) The power scaling process as a function of pump power; (b) the spectrum at maximal output power © Copyright 2018 Cambridge University Press; (c) the beam quality at maximal output power © Copyright 2018 Chinese Laser Press.

  • Figure 7

    (Color online) Output properties of the 5.2 kW monolithic fiber laser oscillator [145] © Copyright 2018 Chinese Laser Press. (a) Output power and optical efficiency; (b) optical spectra at 4970 and 5210 W; (c) beam quality of the monolithic fiber laser oscillator at 5.2 kW.

  • Figure 8

    (Color online) (a) The power scaling process of the 10 kW-level fiber laser system; (b) the far-field beam profile at maximal output power [157].

  • Figure 9

    (Color online) Experimental results of 310 W single-frequency Tm-doped all-fiber amplifier [194] © Copyright 2015 IEEE. (a) Output power; (b) optical spectra (Inset: zoomed-in spectrum); (c) spectrum measured by a scanning Fabry-Perot interferometer to verify the single-frequency operation.

  • Figure 10

    (Color online) Experimental results of the high-efficiency ultrafast Tm-doped fiber amplifier based on tandem pumping [188] © Copyright 2018 Optical Society of America. (a) Output power; (b) measured pulse trains with a repetition rate of 248 MHz.

  • Figure 11

    (Color online) Experimental setup of the kW-level CW CBC system © Copyright 2011 Optical Society of America. Iso: isolator; PM: phase modulator; PA: pre-amplifier; FA: fiber amplifier.

  • Figure 12

    (Color online) Experimental results of CBC of nine CW fiber lasers © Copyright 2011 Optical Society of America.

  • Figure 13

    (Color online) Experimental setup of CBC of seven pulsed fiber lasers © Copyright 2013 The Japan Society of Applied Physics. EOM: electro-optic modulator; AFG: arbitrary function generator; PAMP: pre-amplifier; P-M: phase modulator; AMP: amplifier; PD: photoelectric detector.

  • Figure 14

    (Color online) Normalized intensity in the pinhole and long-exposure intensity pattern of the combined beam.

  • Figure 15

    (Color online) Pulse shapes of a single channel and combined beam © Copyright 2013 The Japan Society of Applied Physics.

  • Figure 16

    (Color online) Experimental results of the 5 kW CPBC system [273]© Copyright 2017 Chinese Laser Press. (a) The relationship between the output laser power and the absorbed pump power of the four amplifiers; (b) combined output power and the combining efficiency as a function of the total injected power.

  • Figure 17

    (Color online) Experimental results of the pulsed CPBC system [277] © Copyright 2018 Astro Ltd. Reproduced by permission of IOP Publishing. (a) The time series with piston phase locking and system optimizing design; (b) the combining efficiency as a function of the combined power; (c) the autocorrelation traces of individual beam and the combined beam.

  • Table 1   Typical research results on single-frequency fiber amplifiers
    Year Institution Configuration Power (W) $M^2$ Polarization Ref.
    2005 University of Southampton, UK Not-all-fiber 264 1.1 PM [107]
    2006 Laser Zentrum Hannover, Germany Not-all-fiber 148 $<$1.2 PM [108]
    2007 Corning, USA Not-all-fiber 502 1.4 NPM [109]
    2007 University of Southampton, UK Not-all-fiber 402 $<$1.1 PM [110]
    2007 University of Southampton, UK Not-all-fiber 511 1.6 NPM [110]
    2008 OFS Laboratories, USA All-fiber 194 1.2 NPM [111]
    2009 Air Force Research Laboratory (AFRL), USA Not-all-fiber 260 $<$1.3 PM [112]
    2011 AFRL, USA All-fiber 203 PM [113]
    2011 University of Michigan, USA Not-all-fiber 511 1.2 PM [114]
    2012 National University of Defense technology (NUDT), China All-fiber 310 1.3 NPM [105]
    2012 Laser Zentrum Hannover, Germany All-fiber 301 1.15 NPM [115]
    2013 Shanghai Institute of Optics and Fine Mechanics (SIOM), China All-fiber 170 1.02 PM [116]
    2013 NUDT, China All-fiber 332 1.4 PM [71]
    2014 AFRL, USA Not-all-fiber 811 $<$1.2 PM [106]
    2016 Laser Zentrum Hannover, Germany Not-all-fiber 158 PM [117]
    2017 NUDT, China All-fiber 414 1.34 PM [28]
  • Table 2   Typical experimental results on narrow-linewidth fiber amplifiers
    Year Institution Configuration Power (kW) $M^2$ Linewidth Polarization Ref.
    2008 Nufern, USA All-fiber 1.01 $<$1.25 8 GHz PM [120]
    2010 Northrop Grumman, USA All-fiber 1.43 25 GHz PM [121]
    2014 Nufern, USA All-fiber 1.50 PM [122]
    2014 Lockheed Martin, USA All-fiber 1.14 1.08 12 GHz PM [103]
    2014 AFRL, USA All-fiber 1.17 1.2 3 GHz NPM [123]
    2015 IPG Photonics, USA All-fiber $>$1.5 1.1 $<$15 GHz NPM [124]
    2015 Shandong HFB Photonics, China All-fiber 2.05 $<$1.4 75 GHz NPM [125]
    2015 University Jena, Germany All-fiber 2.3 $<$1.3 45 GHz NPM[126]
    2015 MIT Lincoln Lab, USA Not-all-fiber 2.55 $<$1.15$<$12 GHz NPM [127]
    2015 IPG Photonics, USAAll-fiber1.03 1.1820 GHz PM [128]
    2016 NUDT, China All-fiber 1.89 $<$1.3 45 GHz PM [25]
    2016 MIT Lincoln Lab, USA Not-all-fiber 3.1 $<$1.15 12 GHz PM [129]
    2016 University Jena, Germany Not-all-fiber 3 1.3 0.17 nm NPM [130]
    2016 AFRL, USA All-fiber 1 1.2 2.5 GHz NPM [131]
    2017 NUDT, China All-fiber 2.43 0.255 nm PM [73]
    2017 University Jena, Germany Not-all-fiber 3.5 1.3 47.4 GHz NPM [132]
    2018 China Academy of Engineering Physics All-fiber 3.5 1.9 0.175 nm NPM [133]
    2018 IPG Photonics, USA All-fiber 2 1.1 30 GHz PM [134]
    2018 IPG Photonics, USA All-fiber 2.5 1.1 30 GHz NPM [134]
    2018 nLight Photonics, USA All-fiber 2.6 20 GHz NPM [135]
    2018 NUDT, China All-fiber 3.94 1.86 0.89 nm @90$%$ energy NPM
  • Table 3   Typical research results on directly broadband fiber oscillator
    Year Institution Configuration Power (kW) $M^2$ Ref.
    2012 Alfalight Inc., USA All-fiber 1 [150]
    2012 JDSU Inc., USA All-fiber 1.2 $<$1.2 [151]
    2012 Rofin, Germany All-fiber 21.3 [152]
    2014 NUDT, China All-fiber 1.5 $<$1.2 [137]
    2014 Coherent Inc., USA Not-all-fiber 3 $<$1.2 [153]
    2016 Fujikura Inc., Japan All-fiber 2 1.2 [154]
    2016 NUDT, China All-fiber 2.5 1.3 [139]
    2017 Fujikura Inc., Japan All-fiber 3 1.3 [147]
    2017 NUDT, China All-fiber 3 1.3 [140]
    2017 NUDT, China All-fiber 4 2.2 [141]
    2018 Fujikura Inc., Japan All-fiber 5 1.3 [148]
    2018 NUDT, China All-fiber 5.2 2.2 [149]
  • Table 4   Typical research results on high power broadband fiber amplifiers
    Year Institution Configuration Pump manner Power (kW) BQ Ref.
    2013 IPG Photonics TDP 20 [160]
    2015 NUDT, China All-fiber LDP 3.15 1.6 [136]
    2016 Tsinghua University, China All-fiber LDP 3.89 [83]
    2016 Huazhong University of Science and Technology, China All-fiber LDP 3 1.3 [161]
    2016 China Academy of Engineering Physics, China All-fiber LDP 5.07 2.3 [162]
    2016 NUDT, China All-fiber TDP 10.1 1.95 [157]
    2017 University Jena, Germany Not-all-fiber LDP 4.3 1.2 [132]
    2017 Tianjin University, China All-fiber LDP 5 1.7 [163]
    2017 Tianjin University, China All-fiber LDP 8 $<$4.3 [163]
    2017 Huazhong University of Science and Technology, China All-fiber LDP 3.7 [164]
    2018 China Academy of Engineering Physics, China All-fiber LDP 11.23 [158]
    2018 Tsinghua University, China All-fiber LDP 6 [165]
    2018 China Academy of Engineering Physics, China All-fiber LDP 10.6 [159]
  • Table 5   Typical research results on different coaxially coherent beam combining techniques
    Year Institution Combining technique Power (kW) $M^2$ Combining efficiency Ref.
    2010 Lockheed Martin, USA RIW 0.1 1.25 80$%$ [250]
    2012 Soreq NRC, Israel HPFC 3 1.17 [275]
    2012 MIT Lincoln Lab, USA DOE 1.93 1.1 79$%$ [276]
    2014 Northrop Grumman, USA DOE 2.4 1.2 80$%$ [217]
    2016 AFRL, USA DOE 5 1.06 82$%$ [248]
    2017 NUDT, China CPBC 2.16 1.2 94.5$%$ [23]
    2017 MIT Lincoln Lab, USA AFPL 1.27 [254]
    2017 NUDT, China CPBC 5.02 1.3 93.8$%$ [273]

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