In this paper, we report a high power single frequency 1030 nm fiber laser with near-diffraction-limited beam quality based on a polarization-maintaining tapered Yb-doped fiber (T-YDF). The T-YDF has advantages of effectively suppressing stimulated Brillouin scattering (SBS) while maintaining good beam quality. As a result, a record output power of 379 W single frequency, linearly polarized, nearly single-mode fiber amplifier operating at 1030 nm is demonstrated. The polarization extinction ratio is as high as 16.3 dB, and the M² is measured to be 1.12. Further, the dependence of the thermal-induced mode instability (TMI) threshold on the polarization state of an input signal laser is investigated for the first time. By changing the polarization state of the injected seed laser, the output power can increase to 550 W while the beam quality can be maintained well (M²=1.47). The slope efficiency of the whole amplifier is about 80%. No sign of SBS appears even at the highest output power and the further brightness scaling of both situations is limited by the TMI effect. To the best of our knowledge, this result is the highest output power of all-fiberized single frequency fiber amplifiers.

中文翻译：

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550 W单频光纤放大器，基于锥形Yb掺杂光纤发射1030 nm波长。

在本文中，我们报告了一种基于保偏锥形掺Yb光纤（T-YDF）的具有近衍射极限光束质量的高功率单频1030 nm光纤激光器。T-YDF具有在保持良好光束质量的同时有效抑制受激布里渊散射（SBS）的优势。结果，证明了在1030 nm下工作的379 W单频，线性偏振，近单模光纤放大器的记录输出功率。极化消光比高达16.3 dB，M ²测得为1.12。此外，首次研究了热致模式不稳定性（TMI）阈值对输入信号激光器的偏振状态的依赖性。通过改变注入的种子激光器的偏振状态，可以将输出功率增加到550 W，同时可以很好地保持光束质量（M ² = 1.47）。整个放大器的斜率效率约为80％。即使在最高输出功率下，也不会出现SBS的迹象，并且两种情况的进一步亮度缩放都受到TMI效果的限制。据我们所知，此结果是全光纤单频光纤放大器的最高输出功率。