Delft, Netherlands, Berkeley, California, and Oxfordshire, UK — QphoX B.V., a Dutch quantum technology startup developing leading frequency conversion systems for quantum applications, Rigetti Computing, Inc. (Nasdaq: RGTI), a pioneer in full-stack quantum-classical computing, and the National Quantum Computing Centre (NQCC), the UK’s national lab for quantum computing, today announced that they have been awarded a multinational grant to perform readout of superconducting qubits using light transmitted over optical fiber.
In a recent demonstration, QphoX and Rigetti validated the potential of this technique by optically reading out the state of a single superconducting qubit1. Optical readout is made possible by microwave-to-optical transduction at the base temperature of the cryostat. This transduction process converts the information contained in the microwave readout pulse into an optical signal carried over optical fiber. This approach could eventually replace conventional microwave amplifiers and coaxial wiring as part of the qubit signal processing chain and thereby offer considerable scaling advantages due to the comparatively low dissipation of the transducer and the negligible passive heat loads from telecommunications optical fiber.
QphoX, Rigetti and the NQCC are partnering to take the next step in this research to realize optical readout of a fully-fledged superconducting quantum computer. In this multinational collaboration, QphoX will scale its optical qubit readout system that will interface with Rigetti’s 9-qubit Novera QPU, enabling optical readout of all qubits in the processor. The combined system will be installed and operated at the NQCC.
“Using light to readout the state of a superconducting qubit will remove a significant amount of heat load on cryogenic systems and therefore allow to overcome one of the critical bottlenecks in building a universal quantum computer. We are excited to take our developments to the next level and work with our partners in demonstrating this critical technology at scale,” says Simon Groeblacher, CEO of QphoX.
“This innovative solution to a well-known scaling challenge is made possible by an open and modular system architecture,” says Dr. Subodh Kulkarni, Rigetti CEO. “Integrating our partners’ technology with our QPU enables us to benefit from even more expertise to accelerate our work towards fault tolerance.”
“Demonstrating optical qubit readout at the system level represents an important step in our mission to advance scalable quantum computing, and we are delighted to host this collaborative work at the NQCC with such innovative project partners,” commented Dr. Michael Cuthbert, Director of NQCC.
The 33-month program is funded by the Rijksdienst voor Ondernemend Nederland (RVO) and Innovate UK via the Eureka network, an intergovernmental organization for research and development funding and coordination.
1van Thiel, T.C., Weaver, M.J., Berto, F. et al. Optical readout of a superconducting qubit using a piezo-optomechanical transducer. Nat. Phys. 21, 401–405 (2025).
About QphoX
QphoX is the leading developer of quantum transduction systems that enable quantum computers to network over optical frequencies. Leveraging decades of progress in photonic, MEMS and superconducting device nanofabrication, their single-photon interfaces bridge the gap between microwave, optical and telecom frequencies to provide essential quantum links between computation, state storage and networking. QphoX is based in Delft, the Netherlands. See qphox.eu for more information.
About Rigetti
Rigetti is a pioneer in full-stack quantum computing. The Company has operated quantum computers over the cloud since 2017 and serves global enterprise, government, and research clients through its Rigetti Quantum Cloud Services platform. In 2021, Rigetti began selling on-premises quantum computing systems with qubit counts between 24 and 84 qubits, supporting national laboratories and quantum computing centers. Rigetti’s 9-qubit Novera™ QPU was introduced in 2023 supporting a broader R&D community with a high-performance, on-premises QPU designed to plug into a customer’s existing cryogenic and control systems. The Company’s proprietary quantum-classical infrastructure provides high-performance integration with public and private clouds for practical quantum computing. Rigetti has developed the industry’s first multi-chip quantum processor for scalable quantum computing systems. The Company designs and manufactures its chips in-house at Fab-1, the industry’s first dedicated and integrated quantum device manufacturing facility. Learn more at rigetti.com.
About the NQCC
The NQCC is the UK’s national lab for quantum computing, dedicated to accelerating the development of quantum computing by addressing the challenges of scaling up the technology. The centre is working with businesses, government, and the research community to deliver quantum computing capabilities for the UK and support the growth of the emerging industry. The NQCC’s programme is being delivered jointly by UKRI’s research councils, EPSRC and STFC. It is a part of the National Quantum Technologies Programme (NQTP) to develop and deliver quantum technologies across the areas of sensing, timing, imaging, communications and computing. The centre is headquartered in a purpose-built facility on STFC’s Rutherford Appleton Laboratory site at the Harwell Campus in Oxfordshire. Visit nqcc.ac.uk for more information.
QphoX Media Contacts:
Simon Gröblacher, CEO, press@qphox.eu