Synchronously pumped optical parametric oscillators (OPOs) are important tools for frequency comb (FC) generation in the mid-IR spectral range, where few suitable laser gain materials exist. For degenerate OPOs, self-phase-locking to the pump FC has been demonstrated. Here, we present a phase noise study of the carrier envelope offset frequency, revealing a $-6\mathrm{dB}$ reduction compared to the pump FC over a wide Fourier frequency range. These results demonstrate that a degenerate OPO can be an ideal coherent frequency divider without any excess noise.

中文翻译：

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简并同步泵浦光参量振荡器的相干分频

同步泵浦光参量振荡器（OPO）是在中红外光谱范围内产生频率梳（FC）的重要工具，那里几乎没有合适的激光增益材料。对于退化的OPO，已经证明了到泵FC的自锁相。在这里，我们对载波包络偏移频率进行了相位噪声研究，揭示了$-6\mathrm{D\; b}$在较宽的傅立叶频率范围内，与泵FC相比，降低了 这些结果表明，退化的OPO可以是理想的相干分频器，而不会产生任何多余的噪声。