High-power and high-quality pulsed fiber lasers with low repetition frequency are widely applied to various fields ranging from basic science to industrial applications. Coherent beam combining (CBC) is a significant method to obtain that beam, but few methods used for large-scale CBC of pulsed fiber lasers with low repetition frequency were presented. To realize it, a new method based on a continuous carrier was designed, where the continuous wave worked as the beacon signal, and the stochastic parallel gradient descent algorithm was employed for phase locking and tilt correction. The beam combining experiment revealed that the combining efficiency of two lasers with a repetition frequency of 15 kHz and a pulse width of 100 ns was 95%, and the fringe contrast in the center of the far-field spot was improved about three times. This method promises to be furtherly applied to combine the pulsed lasers with lower repetition frequency and narrower pulse width. These results pave the way for large-scale CBC of high-power and high-quality pulsed fiber lasers.

中文翻译：

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基于连续载波主动控制的脉冲激光间接相干合束

低重复频率的高功率、高质量脉冲光纤激光器广泛应用于从基础科学到工业应用的各个领域。相干光束组合 (CBC) 是获得该光束的重要方法，但很少有用于低重复频率脉冲光纤激光器的大规模 CBC 的方法。为此，设计了一种基于连续载波的新方法，以连续波为信标信号，采用随机平行梯度下降算法进行锁相和倾斜校正。合束实验表明，两路重复频率为15 kHz、脉冲宽度为100 ns的激光器的合束效率为95%，远场光斑中心的条纹对比度提高了约3倍。该方法有望进一步应用于组合具有较低重复频率和较窄脉冲宽度的脉冲激光。这些结果为高功率和高质量脉冲光纤激光器的大规模 CBC 铺平了道路。