Supercontinuum generation and soliton microcomb formation both represent key techniques for the formation of coherent, ultrabroad optical frequency combs, enabling the RF-to-optical link. Coherent supercontinuum generation typically relies on ultrashort pulses with kilowatt peak power as a source, and so are often restricted to repetition rates less than 1 GHz. Soliton microcombs, conversely, have an optical conversion efficiency that is best at ultrahigh repetition rates such as 1 THz. Neither technique easily approaches the microwave domain, i.e., 10 s of GHz, while maintaining an ultrawide spectrum. Here, we bridge the efficiency gap between the two approaches in the form of resonant supercontinuum generation by driving a dispersion-engineered photonic-chip-based microresonator with picosecond pulses of the order of 1-W peak power. We generate a smooth 2200-line soliton-based comb at an electronically detectable 28 GHz repetition rate. Importantly, we observe that solitons exist in a weakly bound state with the input pulse where frequency noise transfer from the input pulses is suppressed even for offset frequencies 100 times lower than the linear cavity decay rate. This transfer can be reduced even further by driving the cavity asynchronously, ensuring the frequency comb stays coherent even for optical lines very far from the pump center.

中文翻译：

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通过脉冲驱动的克尔微谐振器孤子实现基于光子芯片的谐振超连续谱

超连续谱产生和孤子微梳形成都代表了形成相干、超宽光频梳的关键技术，使射频到光链路成为可能。相干超连续谱生成通常依赖于具有千瓦峰值功率的超短脉冲作为源，因此通常仅限于小于 1 GHz 的重复率。相反，孤子微梳具有在超高重复率（例如 1 THz）下最佳的光学转换效率。两种技术都无法轻松接近微波域，即 10 s GHz，同时保持超宽频谱。在这里，我们通过以 1W 峰值功率的皮秒脉冲驱动基于色散设计的光子芯片的微谐振器，以谐振超连续谱产生的形式弥合了两种方法之间的效率差距。我们以电子可检测的 28 GHz 重复率生成平滑的 2200 线基于孤子的梳。重要的是，我们观察到孤子与输入脉冲以弱束缚状态存在，即使偏移频率比线性腔衰减率低 100 倍，来自输入脉冲的频率噪声转移也被抑制。这种传输可以通过异步驱动腔进一步减少，确保频率梳即使对于距离泵浦中心很远的光线路也保持一致。