Precision optical-frequency and phase synchronization over fibre is critical for a variety of applications, from timekeeping to quantum optics. Such applications utilize ultra-coherent sources based on stabilized table-top laser systems. Chip-scale versions of these systems may dramatically broaden the application landscape by reducing the cost, size and power of such exquisite sources. Links based on the required narrow-linewidth integrated lasers, compact reference cavities and control methodologies have not yet been presented. Here, we demonstrate an optically synchronized link that achieves an ultralow residual phase error variance of 3 × 10⁻⁴ rad² at the receiver, using chip-scale stabilized lasers with laser linewidth of ~30 Hz and instability below 2 × 10⁻¹³ at 50 ms. This performance is made possible with integrated Brillouin lasers, compact reference cavities and a novel low-bandwidth optical-frequency-stabilized phase-locked loop. These results demonstrate a path towards low-power, precision applications including distributed atomic clocks, quantum links, database synchronization and digital-signal-processor-free coherent fibre interconnects.

光纤上的精密光学频率和相位同步对于从计时到量子光学的各种应用至关重要。此类应用利用基于稳定桌面激光系统的超相干光源。这些系统的芯片级版本可以通过降低此类精致光源的成本、尺寸和功率来显着拓宽应用领域。尚未提出基于所需窄线宽集成激光器、紧凑型参考腔和控制方法的链接。在这里，我们演示了一种光学同步链路，该链路在接收器处实现了 3 × 10 ^-4  rad ^{2的超低残余相位误差方差，使用具有~30 Hz 激光线宽和低于 2 × 10 -13}的不稳定性的芯片级稳定激光器在 50 毫秒。这种性能是通过集成布里渊激光器、紧凑的参考腔和新颖的低带宽光学频率稳定锁相环实现的。这些结果展示了一条通往低功耗、精密应用的道路，包括分布式原子钟、量子链路、数据库同步和无数字信号处理器的相干光纤互连。