Steinkopff Albrecht, Jauregui Cesar, Aleshire Christopher, Klenke Arno, Limpert Jens
Opt Express. 2020 Dec 7;28(25):38093-38105. doi: 10.1364/OE.410614.
In this work we analyze the power scaling potential of amplifying multicore fibers (MCFs) used in coherently combined systems. In particular, in this study we exemplarily consider rod-type MCFs with 2 × 2 up to 10 × 10 ytterbium-doped cores arranged in a squared pattern. We will show that, even though increasing the number of active cores will lead to higher output powers, particular attention has to be paid to arising thermal effects, which potentially degrade the performance of these systems. Additionally, we analyze the influence of the core dimensions on the extractable and combinable output power and pulse energy. This includes a detailed study on the thermal effects that influence the propagating transverse modes and, in turn, the amplification efficiency, the combining efficiency, the onset of nonlinear effect, as well as differences in the optical path lengths between the cores. Considering all these effects under rather extreme conditions, the study predicts that average output powers higher than 10 kW from a single 1 m long ytterbium-doped MCF are feasible and femtosecond pulses with energies higher than 400 mJ can be extracted and efficiently recombined in a filled-aperture scheme.
在这项工作中，我们分析了用于相干合成系统的多芯光纤（MCF）的功率扩展潜力。具体而言，在本研究中，我们示例性地考虑了具有2×2至10×10排列成方形图案的掺镱纤芯的棒状MCF。我们将表明，尽管增加有源纤芯的数量会导致更高的输出功率，但必须特别注意由此产生的热效应，这些热效应可能会降低这些系统的性能。此外，我们分析了纤芯尺寸对可提取和可合成的输出功率及脉冲能量的影响。这包括对影响传播横向模式的热效应的详细研究，进而影响放大效率、合成效率、非线性效应的起始，以及纤芯之间光程长度的差异。在相当极端的条件下考虑所有这些效应，该研究预测，从一根1米长的掺镱MCF获得高于10千瓦的平均输出功率是可行的，并且在填充孔径方案中可以提取并有效合成能量高于400毫焦的飞秒脉冲。
