Optical frequency comb technology has been the cornerstone for scientific breakthroughs in precision metrology. In particular, the unique phase-coherent link between microwave and optical frequencies solves the long-standing puzzle of precision optical frequency synthesis. While the current bulk mode-locked laser frequency comb has had great success in extending the scientific frontier, its use in real-world applications beyond the laboratory setting remains an unsolved challenge due to the relatively large size, weight and power consumption. Recently microresonator-based frequency combs have emerged as a candidate solution with chip-scale implementation and scalability. The wider-system precision control and stabilization approaches for frequency microcombs, however, requires external nonlinear processes and multiple peripherals which constrain their application space. Here we demonstrate an internal phase-stabilized frequency microcomb that does not require nonlinear second-third harmonic generation nor optical external frequency references. We demonstrate that the optical frequency can be stabilized by control of two internally accessible parameters: an intrinsic comb offset ξ and the comb spacing f_rep. Both parameters are phase-locked to microwave references, with phase noise residuals of 55 and 20 mrad respectively, and the resulting comb-to-comb optical frequency uncertainty is 80 mHz or less. Out-of-loop measurements confirm good coherence and stability across the comb, with measured optical frequency instability of 2 × 10⁻¹¹ at 20-second gate time. Our measurements are supported by analytical theory including the cavity-induced modulation instability. We further describe an application of our technique in the generation of low noise microwaves and demonstrate noise suppression of the repetition rate below the microwave stabilization limit achieved.

光学频率梳技术一直是精密计量科学突破的基石。特别是，微波和光频率之间独特的相位相干链接解决了长期以来精确的光频率合成难题。尽管当前的体锁模激光频率梳在扩展科学前沿方面已经取得了巨大的成功，但是由于其相对较大的尺寸，重量和功耗，其在实验室环境之外的实际应用中仍然面临着尚未解决的挑战。最近，基于微谐振器的频率梳已经成为具有芯片级实现和可扩展性的候选解决方案。但是，针对频率微梳的更广泛的系统精度控制和稳定方法，需要外部非线性过程和多个外围设备，这限制了它们的应用空间。在这里，我们演示了一个内部相位稳定的频率微梳，它不需要非线性的二次三次谐波产生，也不需要光学外部频率基准。我们证明，可以通过控制两个内部可访问参数来稳定光频率：本征梳齿偏移ξ和梳齿间距f _rep。这两个参数都被锁相到微波参考，相位噪声残差分别为55和20 mrad，所产生的梳齿光学频率不确定度为80 mHz或更小。环外测量结果证实了整个梳子具有良好的相干性和稳定性，在20秒选通时间所测得的光学频率不稳定性为2×10 ^-11。我们的测量得到包括空腔引起的调制不稳定性在内的分析理论的支持。我们进一步描述了我们的技术在低噪声微波产生中的应用，并展示了重复频率的噪声抑制低于所达到的微波稳定极限。