Precise optical synchronization of high-speed electronics with microcombs

forthcoming

Laser frequency combs based on mode-locked lasers are extraordinary photonic devices that have revolutionized precision frequency synthesis and metrology in the 21st century. They have enabled groundbreaking developments such as optical clocks, femtosecond-level timing synchronization, and ultra-pure microwave generation. Microresonator-based frequency combs (microcombs) offer a transformative potential to reduce the complexity and size of traditional laser frequency combs. Recent advances in dissipative Kerr solitons have demonstrated the viability of these chip-scale devices, which can be manufactured at the wafer level through semiconductor processing techniques. However, microcombs still fall short in stability and phase noise compared to their non-integrated, mode-locked counterparts due to intrinsic scaling limitations when operating at the chip scale. This proposal seeks to bridge this performance gap by developing high-performance, octave-spanning microcombs with photodetectable repetition rates using innovative arrangements of coupled microresonators. These advancements will enable single-point optical frequency division, whereby the comb’s degrees of freedom will be determined by an optical frequency reference. The project will explore 3D integration of ultralow-loss silicon nitride with advanced materials, aiming to create high-performance microcomb-based systems on a chip, and lay the foundation for novel optoelectronic synchronization architectures in datacenters. These innovations address key challenges in energy consumption and capacity scaling in datacenters and large scaling computing architectures, paving the way for future advancements in global communication infrastructure.