• High Power Laser Science and Engineering
  • Vol. 9, Issue 2, 02000e20 (2021)
Wei Gao1、2、3, Wenhui Fan1、3、5, Pei Ju1、3, Gang Li1、3, Yanpeng Zhang2、*, Aifeng He4, Qi Gao1、3, and Zhe Li1、3
Author Affiliations
  • 1State Key Laboratory of Transient Optics and Photonics, Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi’an710119, China
  • 2Key Laboratory for Physical Electronics and Devices of the Ministry of Education & Shaanxi Key Laboratory of Information Photonic Technique, Xi’an Jiaotong University, Xi’an710049, China
  • 3University of Chinese Academy of Sciences, Beijing100049, China
  • 4Key Laboratory on Applied Physics and Chemistry, Shaanxi Applied Physics and Chemistry Research Institute, Xi’an710061, China
  • 5Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan030006, China
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    DOI: 10.1017/hpl.2021.13 Cite this Article
    Wei Gao, Wenhui Fan, Pei Ju, Gang Li, Yanpeng Zhang, Aifeng He, Qi Gao, Zhe Li. Effective suppression of mode distortion induced by stimulated Raman scattering in high-power fiber amplifiers[J]. High Power Laser Science and Engineering, 2021, 9(2): 02000e20 Copy Citation Text show less

    Abstract

    Mode distortion induced by stimulated Raman scattering (SRS) has become a new obstacle for the further development of high-power fiber lasers with high beam quality. Here, an approach for effective suppression of the SRS-induced mode distortion in high-power fiber amplifiers has been demonstrated experimentally by adjusting the seed power (output power of seed source) and forward feedback coefficient of the rear port in the seed source. It is shown that the threshold power of the SRS-induced mode distortion can be increased significantly by reducing the seed power or the forward feedback coefficient. Moreover, it has also been found that the threshold power is extremely sensitive to the forward feedback power value from the rear port. The influence of the seed power on the threshold power can be attributed to the fact that the seed power plays an important role in the effective length of the gain fiber in the amplifier. The influence of the forward feedback coefficient on the threshold power can be attributed to the enhanced SRS configuration because the end surface of the rear port together with the fiber in the amplifier constitutes a half-opening cavity. This suppression approach will be very helpful to further develop the high-power fiber amplifiers with high beam quality.

    1 Introduction

    High-power fiber lasers have found a wide variety of applications in industry, science, and defense owing to high conversion efficiency, robustness, easy thermal management, and especially excellent beam quality[13]. The large-mode-area (LMA) double-cladding gain fibers and high-brightness semiconductor laser diodes (LDs) lead to an exponential evolution on the output power of fiber lasers in the past two decades[4]. However, the evolution is suffering from a sudden halt owing to mode degradation phenomena[5,6].

    Wei Gao, Wenhui Fan, Pei Ju, Gang Li, Yanpeng Zhang, Aifeng He, Qi Gao, Zhe Li. Effective suppression of mode distortion induced by stimulated Raman scattering in high-power fiber amplifiers[J]. High Power Laser Science and Engineering, 2021, 9(2): 02000e20
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