ERC Proof of Concept Grant to Johannes Fink

Large-scale quantum computation will likely rely on distributed quantum computing across multiple processors and the development of a quantum internet. However, these approaches are based on superconducting qubits that use electrical signals at ultracold temperatures, making room-temperature connections problematic. Institute of Science and Technology Austria (ISTA) physicists recently demonstrated a fully optical readout of superconducting qubits using an electro-optic transducer. They are now awarded an ERC Proof of Concept grant worth 150,000 euros to help commercialize their technology.

Quantum computers hold the promise of one day outperforming classical computers in solving specific problems. However, they remain research endeavors as quantum scientists around the globe rush to overcome myriad technological hurdles that prevent scaling them up. Among the most promising quantum computing platforms available today are superconducting qubits. They are made by cooling tiny electrical circuits to ultracold temperatures where they lose all electrical resistance and can thus maintain a flowing current indefinitely. These superconducting qubits require tremendous cooling and elaborate machinery to operate using electrical signals, and are thus difficult to scale up. It follows that any future quantum network will necessarily rely on optical frequencies that can travel long distances at room temperature.

Earlier this year, researchers from Professor Johannes Fink’s group at the Institute of Science and Technology Austria (ISTA) achieved a fully optical readout of superconducting qubits using an electro-optic transducer. With this approach, they were able to ‘translate’ the electrical signal into an optical one, and vice versa, and greatly reduce the electrical components of a superconducting quantum computer laboratory prototype. Their work demonstrated that an optical fiber could, in principle, soon connect two superconducting qubits in two separate quantum computers. Now, the European Research Council has awarded the team an ERC Proof of Concept (PoC) grant to help bridge the gap between the results of their pioneering research and the early phases of its commercialization.

From a laboratory prototype to a plug-and-play device

The team’s technical advancement, published earlier this year in Nature Physics, was no easy endeavor. Firstly, the microwave (electrical) and optical signals have an energy gap of more than four orders of magnitude. In addition, only a handful of electro-optic transducers engineered to detect and relay quantum signals exist in a few specialized research labs around the world, with no commercial availability. “So far, successfully assembling one of these devices has been quite challenging, requiring skill and sometimes luck, particularly for use at ultracold temperatures where superconducting qubits operate,” says Fink. “With the present grant, we will develop robust microchip-based optical coupling methods, which will advance our technology from a proof-of-principle lab experiment to an actual product with utility.” ISTA postdoc Rishabh Sahu, who substantially contributed to the project proposal, adds, “If successful, the present project will allow us to develop a plug-and-play device that does not require any special skills to operate. This would make our technology an attractive option for a possible future spin-off.”

Beyond its applications in the development of a future quantum internet, advancing the electro-optic transducer could also have more ‘classical’ applications. These include radars, remote sensing, and spectroscopy, where optically detecting microwave and terahertz frequency signals is beneficial.

A ‘top-up’ grant to help explore a project’s commercial or societal potential

Two calls for ERC PoC grants will take place this year. The results of the first call were announced today. The ISTA researchers’ project, titled “Integrated optical coupling for low-loss electro-optic interconnects” (CoupledEOT), is one of three ERC PoC grants awarded to researchers based in Austria.

The ERC PoC grant scheme is open only to researchers who currently hold, or have previously been awarded, ERC frontier research grants. These top-up grants help the researchers explore the commercial or societal potential of the findings they made through their ERC projects. The objective is to enable ERC-funded ideas to progress on the path from groundbreaking research towards innovation. Originally from Vorarlberg, Austria, ISTA Professor Johannes Fink has already benefited from an ERC Starting Grant and has an ongoing ERC Consolidator grant.

Each ERC PoC grant is endowed with 150,000 Euros over eighteen months and is designed to help ERC grantees bridge the gap between the results of their pioneering research and the early phases of its commercialization or societal application. The grant scheme is part of Horizon Europe, the EU’s research and innovation program.