We present a regenerative amplifier (RA) based on Yb:YAG single-crystal fiber (SCF) and nonlinear amplifying loop mirror (NALM) fiber oscillator. The home-made all-fiber NALM oscillator is constructed with polarization maintaining (PM) fibers for improved environmental stability, delivering a stable pulse train. The seed is directly amplified in a single stage without using CPA technique. 21 W, $105~\mu \text{J}$ , 2.4 ps at 200 kHz repetition rate with beam quality of 1.3 has been achieved. A remarkable optical gain of 57.4 dB is obtained with a seed injection of 190 pJ. Further increase in average power is expected.

中文翻译：

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基于 Yb:YAG SCF 和 NALM 光纤振荡器的 21 W、105 μJ 再生放大器

我们提出了一种基于 Yb:YAG 单晶光纤 (SCF) 和非线性放大环路镜 (NALM) 光纤振荡器的再生放大器 (RA)。自制的全光纤 NALM 振荡器由保偏 (PM) 光纤构成，以提高环境稳定性，提供稳定的脉冲序列。种子在单个阶段直接扩增，无需使用 CPA 技术。21 瓦， $105~\mu \text{J}$ , 在 200 kHz 重复率下达到 2.4 ps，光束质量为 1.3。以 190 pJ 的种子注入获得了 57.4 dB 的显着光学增益。预计平均功率将进一步增加。