Abstract. Our study describes the development of coherent beam combining of an array of nine fiber lasers using an all-optical ring cavity feedback loop based on a diffractive optical element to achieve a single-aperture output. Nine 300-mW Yb-doped fiber amplifier beams arranged in a 1 × 9 end-cap array were combined to achieve a single-aperture beam with a power of 739 mW and a beam quality (M2) of 1.18 with 21.5% combining efficiency. The optical spectra, far-field distributions, and time-domain characteristics of the combined beams were investigated under open- and closed-loop conditions. Under open-loop conditions, the far-field coherent visibility changed constantly from 72.1% to 90.9% and the fluctuation intensity was strong. Under closed-loop conditions, the system achieved a steady state with a visibility of 98.6% and an average feedback intensity of 0.4 V, indicating the occurrence of phase locking. Furthermore, mode hopping was observed when there were more than four channels in a combination. However, the system interference pattern remained stable. Comprehensive research on the relevant literature indicated that novel filled-aperture CBC was achieved using an all-optical ring cavity feedback loop based on a DOE.

中文翻译：

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基于衍射光学元件的全光环腔反馈回路的九光纤激光器阵列相干合束

摘要。我们的研究描述了使用基于衍射光学元件的全光环腔反馈回路实现单孔径输出的九个光纤激光器阵列的相干光束组合的发展。将排列在 1×9 端帽阵列中的 9 条 300mW 掺镱光纤放大器光束组合起来，实现了功率为 739 mW、光束质量 (M2) 为 1.18、组合效率为 21.5% 的单孔径光束。在开环和闭环条件下研究了组合光束的光谱、远场分布和时域特性。在开环条件下，远场相干能见度从72.1%不断变化到90.9%，波动强度强。在闭环条件下，系统达到了能见度为 98 的稳定状态。6% 和 0.4 V 的平均反馈强度，表明发生了锁相。此外，当组合中的通道超过四个时，会观察到模式跳跃。然而，系统干涉图保持稳定。对相关文献的综合研究表明，使用基于 DOE 的全光环腔反馈回路实现了新颖的填充孔径 CBC。