Our work with Prof. Hayun Chung's group (Korea University) on femtosecond-precision electronic clock distribution in CMOS chips by injecting frequency comb-extracted photocurrent pulses is published at Nature Communications. A clock distribution network (CDN) is a ubiquitous on-chip element that provides synchronized clock signals to all different circuit blocks in the chip. To maximize the chip performance, today's CDN demands lower jitter, skew, and heat dissipation. We demonstrated femtosecond-precision distribution of electronic clocks using driver-less CDNs injected by photocurrent pulses. Femtosecond-level on-chip jitter and skew could be achieved for GHz-rate clocking of CMOS chips by combining ultralow comb-jitter, multiple driver-less metal-meshes, and active skew control. The elimination of clock drivers could significantly reduce on-chip heat dissipation from clock distribution as well. This work shows the potential of optical frequency combs for distributing high-quality clock signals inside high-performance integrated circuits, including 3D integrated circuits. This work was also featured in Research Highlights of May 2023 issue of Nature Electronics ("Chips with a pulse").

For further reading:
M. Hyun et al, "Femtosecond-precision electronic clock distribution in CMOS chips by injecting frequency comb-extracted photocurrent pulses," Nature Communications 14, 2345 (2023)
S. Thomas, "Chips with a pulse," Nature Electronics 6, 330 (2023)