We report on the generation of a mid-infrared (mid-IR) frequency comb with a maximum average output power of 250 mW and tunability in the 2.7–4.0 μm region. The approach is based on a single-stage difference frequency generation (DFG) starting from a compact Yb-doped fiber laser system. The repetition rate of the near-infrared (NIR) comb is locked at 75 MHz. The phase noise of the repetition rate in the offset-free mid-IR comb system is measured and analyzed. Except for the intrinsic of NIR comb, environmental noise at low frequency and quantum noise at high frequency from the amplifier chain and nonlinear spectral broadening are the main noise sources of broadening the linewidth of comb teeth, which limits the precision of mid-IR dual-comb spectroscopy.

中文翻译：

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通过紧凑型激光系统产生的差频产生 2.7–4.0 μm 范围内的中红外光学频率梳

我们报告了中红外 (mid-IR) 频率梳的生成，该频率梳的最大平均输出功率为 250 mW，并且在 2.7-4.0 μm 区域内具有可调谐性。该方法基于从紧凑型掺镱光纤激光器系统开始的单级差频生成 (DFG)。近红外 (NIR) 梳的重复频率锁定在 75 MHz。测量和分析了无偏移中红外梳状系统中重复率的相位噪声。除了近红外梳的本征外，来自放大器链的低频环境噪声和高频量子噪声以及非线性光谱展宽是梳齿线宽展宽的主要噪声源，限制了中红外双频的精度。梳状光谱。