A resonant metamaterial clock distribution network for superconducting logic

Abstract

A metamaterial-based resonant clock network can provide energy-efficient power delivery to large superconducting digital systems.

Clock distribution is central to digital technology and influences circuit performance, interconnect overhead and efficiency. However, ensuring reliable clock distribution across large digital systems with low skew and jitter-and in the presence of device variations and thermal noise-is a design challenge. Here we report a superconducting metamaterial resonant clock network that can provide energy-efficient power delivery to large superconducting digital systems. The resonant clock network is based on a metamaterial design with an infinite-wavelength zeroth-order resonance mode and utilizes the ultralow Joule loss of superconductors at microwave frequencies. With this approach, we perform S-parameter measurements for a 10 GHz design and validate a digital reciprocal quantum logic circuit with 48,000 junctions operating at 3.5 GHz. The network supports uniform power distribution with less than 1 dB variation across a 3 x 3 mm(2) active chip area and around 30% power efficiency. Static power dissipation is 28 mu W, which is similar to that of active devices.