Control and readout of a superconducting qubit using a photonic link

Published

March 24, 2021

Author(s)

Florent Lecocq, Franklyn Quinlan, Katarina Cicak, Joe Aumentado, Scott Diddams, John Teufel

Abstract

Delivering on the revolutionary promise of a universal quantum computer will require processors with millions of quantum bits (qubits). In superconducting quantum processors, each qubit is individually addressed with microwave signal lines that connect room-temperature electronics to the cryogenic environment of the quantum circuit. The complexity and heat load associated with the multiple coaxial lines per qubit limits the maximum possible size of a processor to a few thousand qubits. Here we introduce a photonic link using an optical fibre to guide modulated laser light from room temperature to a cryogenic photodetector, capable of delivering shot-noise-limited microwave signals directly at millikelvin temperatures. By demonstrating high-fidelity control and readout of a superconducting qubit, we show that this photonic link can meet the stringent requirements of superconducting quantum information processing. Leveraging the low thermal conductivity and large intrinsic bandwidth of optical fibre enables the efficient and massively multiplexed delivery of coherent microwave control pulses, providing a path towards a million-qubit universal quantum computer.

Citation

Nature

Volume

591

Pub Type

Journals

Download Paper

DOI Link

Keywords

quantum computing, photonics, microwave, superconductivity, cryogenics, qubit

Citation

Lecocq, F. , Quinlan, F. , Cicak, K. , Aumentado, J. , Diddams, S. and Teufel, J. (2021), Control and readout of a superconducting qubit using a photonic link, Nature, [online], https://doi.org/10.1038/s41586-021-03268-x (Accessed October 9, 2025)