6 kW Single Stage Narrow Linewidth Fiber Amplifier Based on the Balance Between Mode Instability and Nonlinear Effects

Single-stage high-power narrow-linewidth fiber laser has been investigated intensively recently because of its simple and robust configuration and great potential in spectral/coherent beam combination. In this work, a 6 kW narrow-linewidth fiber amplifier was experimentally achieved based...

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Bibliographic Details
Main Authors: Xin Tian, Binyu Rao, Meng Wang, Xiaoming Xi, Baolai Yang, Zilun Chen, Hu Xiao, Xiaolin Wang, Pengfei Ma, Zefeng Wang, Jinbao Chen
Format: Article
Language:English
Published: IEEE 2023-01-01
Series:IEEE Photonics Journal
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Online Access:https://ieeexplore.ieee.org/document/10226348/
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Summary:Single-stage high-power narrow-linewidth fiber laser has been investigated intensively recently because of its simple and robust configuration and great potential in spectral&#x002F;coherent beam combination. In this work, a 6 kW narrow-linewidth fiber amplifier was experimentally achieved based on a fiber oscillator seed. By employing a few-mode ytterbium-doped fiber, the spectral broadening and SRS effects are both significantly mitigated. Combined with a wavelength-stabilized 981 nm pump source, the threshold of transverse mode instability is improved, then, a maximum output power of 6020 W at the central wavelength 1080 nm was achieved with 3-dB bandwidth of &#x223C;0.37 nm and optical-to-optical efficiency of &#x223C;85.6&#x0025;. The mode instability and nonlinear effects were balanced well. The measured beam quality and the signal to Raman ratio were M<sup>2</sup>&#x223C;2.7 and &#x223C;27 dB, respectively. This work shows the great potential of such amplification structure for the power scaling of high-power narrow-linewidth fiber lasers.
ISSN:1943-0655