CryoCMOS RF multiplexer for superconducting qubit control, readout and flux biasing at millikelvin temperatures with picowatt power consumption

TL;DR

This paper presents a cryogenic CMOS RF multiplexer operating at 10 millikelvin with ultra-low power consumption, enabling scalable quantum system control and readout with minimal impact on qubit coherence.

Contribution

It introduces a cryoCMOS RF multiplexer capable of operating at millikelvin temperatures with record-low power, high isolation, and minimal qubit coherence impact, advancing scalable quantum control.

Findings

Operates at 10 mK with 200 pW power consumption

Provides < 2 dB insertion loss and > 30 dB isolation from DC to 8 GHz

Marginally affects qubit coherence times (~100 microseconds)

Abstract

Large-scale cryogenic quantum systems are constrained by an input-output bottleneck between room-temperature electronics and millikelvin stages, particularly in superconducting qubit platforms. This bottleneck is most acute for output lines, where bulky and expensive microwave components limit scalability. A promising approach for scalable characterization and testing is to perform signal multiplexing directly at the qubit plane. We demonstrate a cryogenic CMOS (cryoCMOS) RF multiplexer operating at 10 millikelvin with record-low static power consumption of 200 pW. The device provides < 2 dB insertion loss and > 30 dB isolation across DC-8 GHz. Direct connection to transmon qubits marginally affects coherence times in the range of 100 microseconds, enabling multiplexing of readout, flux and, in principle, XY drive lines. This work introduces cryoCMOS multiplexers as valuable tools for scalable, high-throughput cryogenic characterization and testing, and advances co-integrated quantum-classical control for future large-scale quantum processors.