Microcombs—optical frequency combs generated in microresonators—have advanced tremendously in the past decade, and are advantageous for applications in frequency metrology, navigation, spectroscopy, telecommunications, and microwave photonics. Crucially, microcombs promise fully integrated miniaturized optical systems with unprecedented reductions in cost, size, weight, and power. However, the use of bulk free-space and fiber-optic components to process microcombs has restricted form factors to the table-top. Taking microcomb-based optical frequency synthesis around 1550 nm as our target application, here, we address this challenge by proposing an integrated photonics interposer architecture to replace discrete components by collecting, routing, and interfacing octave-wide microcomb-based optical signals between photonic chiplets and heterogeneously integrated devices. Experimentally, we confirm the requisite performance of the individual passive elements of the proposed interposer—octave-wide dichroics, multimode interferometers, and tunable ring filters, and implement the octave-spanning spectral filtering of a microcomb, central to the interposer, using silicon nitride photonics. Moreover, we show that the thick silicon nitride needed for bright dissipative Kerr soliton generation can be integrated with the comparatively thin silicon nitride interposer layer through octave-bandwidth adiabatic evanescent coupling, indicating a path towards future system-level consolidation. Finally, we numerically confirm the feasibility of operating the proposed interposer synthesizer as a fully assembled system. Our interposer architecture addresses the immediate need for on-chip microcomb processing to successfully miniaturize microcomb systems and can be readily adapted to other metrology-grade applications based on optical atomic clocks and high-precision navigation and spectroscopy.

微梳——在微谐振器中产生的光学频率梳——在过去十年中取得了巨大进步，有利于频率计量、导航、光谱学、电信和微波光子学等领域的应用。至关重要的是，微梳有望实现完全集成的小型化光学系统，并以前所未有的方式降低成本、尺寸、重量和功率。然而，使用大量自由空间和光纤组件来处理微梳限制了桌面的形状因素。以 1550 nm 附近基于微梳的光频率合成为我们的目标应用，在这里，我们通过提出一个集成的光子插入器架构来解决这一挑战，通过收集、路由、在光子小芯片和异构集成设备之间连接基于倍频程微梳的光信号。通过实验，我们确认了所提出的内插器的各个无源元件的必要性能——倍频宽二向色镜、多模干涉仪和可调谐环形滤波器，并使用氮化硅实现了内插器中央微梳的八度跨越光谱滤波光子学。此外，我们表明，明亮耗散克尔孤子生成所需的厚氮化硅可以通过倍频程带宽绝热倏逝耦合与相对较薄的氮化硅中介层集成，这表明了未来系统级整合的途径。最后，我们在数值上证实了将所提出的插入器合成器作为一个完全组装的系统进行操作的可行性。我们的中介层架构满足了对片上微梳处理的迫切需求，以成功地使微梳系统小型化，并且可以很容易地适应基于光学原子钟和高精度导航和光谱学的其他计量级应用。