Manufacturable chipset developed for quantum computing

PsiQuantum has announced Omega, a quantum photonic chipset purpose-built for utility-scale quantum computing. Featured in a paper in Nature, the chipset contains all the advanced components required to build million-qubit-scale quantum computers and deliver on the promise of this technology. Every photonic component is demonstrated with state-of-the-art performance.

The paper shows high-fidelity qubit operations, and a simple, long-range chip-to-chip qubit interconnect — a key enabler to scale that has remained challenging for other technologies. The chips are made in a high-volume semiconductor fab, representing a new level of technical maturity and scale in a field that is often thought of as being confined to research labs.

“For more than 25 years it has been my conviction that in order for us to realise a useful quantum computer in my lifetime, we must find a way to fully leverage the unmatched capabilities of the semiconductor industry. This paper vindicates that belief,” said Professor Jeremy O’Brien, PsiQuantum Co-founder & CEO.

Designed by PsiQuantum and manufactured at GlobalFoundries in New York, the new chipset integrates these advances into high-volume, industrially proven processes — ready for large-scale systems integration. PsiQuantum’s approach is based on using single photons — particles of light — which are then manipulated using silicon photonic chip technology originally developed for telecom and data centre networking applications.

For quantum applications, the company had to improve performance well beyond the state-of-the-art, and introduced new materials into the fab, including a superconducting material used for efficient single-photon detection, and barium titanate (BTO), an advanced material for low-loss, high-speed optical switching which is developed and produced by PsiQuantum in San Jose, California. The company also had to overcome challenges with background noise and low-temperature operation of the chip to demonstrate the circuit performance detailed in the paper — PsiQuantum’s latest measurements include 99.98% single-qubit state preparation and measurement fidelity, 99.5% two-photon quantum interference visibility, and 99.72% chip-to-chip quantum interconnect fidelity.

PsiQuantum’s founding team performed the world’s first lab demonstration of a two-qubit logic gate using single photons in Brisbane, Australia over 20 years ago, invented integrated quantum photonics and ‘fusion-based’ quantum computing, and made a prototype quantum processor available via the cloud in 2013. Since then, the team has focused on the scaling, performance and manufacturing challenges associated with building million-qubit-scale systems essential for commercially valuable applications.

PsiQuantum has also introduced an entirely new cooling solution for quantum computers — eliminating the iconic ‘chandelier’ dilution refrigerator in favour of a simpler, more powerful and more manufacturable cuboid design, closer to a data centre server rack. The Nature paper shares some details on this new approach to cooling, which is now deployed at PsiQuantum’s UK facility and was used for many of the performance results described.

Thanks to these advancements, PsiQuantum now has the technology to manufacture and cool vast numbers of quantum chips. While the company must continue to improve the performance, integration and yield of the devices, there is no ‘next step’ in terms of manufacturing maturity — GlobalFoundries is a “tier-1” fab. PsiQuantum has characterised millions of devices on thousands of wafers and currently performs around half a million measurements each month.

PsiQuantum’s focus is now on wiring these chips together across racks, into increasingly large-scale multi-chip systems — work the company is now expanding through its partnership with the U.S. Department of Energy at SLAC National Accelerator Laboratory in Menlo Park, California as well as a new manufacturing and testing facility in Silicon Valley. While chip-to-chip networking remains a hard research problem for many other approaches, photonic quantum computers have the intrinsic advantage that photonic qubits can be networked using standard telecom optical fibre without any conversion between modalities, and PsiQuantum has already demonstrated high-fidelity quantum interconnects over distances up to 250 m.

In 2024, PsiQuantum announced two landmark partnerships with the Australian federal and Queensland state governments, as well as the State of Illinois and the City of Chicago, to build its first utility-scale quantum computers in Brisbane and Chicago. Recognising quantum as a sovereign capability, these partnerships underscore the urgency and race towards building million-qubit systems. Later this year, PsiQuantum will break ground on Quantum Compute Centres at both sites, where the first utility-scale, million-qubit systems will be deployed.

“Omega moves us beyond a science project,” said Pete Shadbolt, PsiQuantum Co-founder & Chief Scientific Officer. “Before we started PsiQuantum, my cofounders and I were in a university lab playing around with a couple of qubits but we knew then that the platform we were using was sorely deficient —  we knew that we needed millions of qubits and we knew that implied getting into a mature fab, integration of unlikely components together into a single platform, and climbing a performance curve that at the time seemed borderline impossible. It has been amazing to see how the team has executed on those plans from a decade ago, and it is tremendously exciting to now have the technology in our hands that we will use to build the first commercially useful systems,” Shadbolt said.

Image credit: iStock.com/PonyWang