One photon at a time: the company bringing quantum devices to life

2025 is the Year of Quantum Science and Technology. Armed with deep research and timely dose of EU funding, what began as a risky idea in Copenhagen has become one of Europe's most scientifically and commercially promising next-generation quantum companies.

The initiative highlights successful stories from projects funded by the European Innovation Council (EIC). Featured in DeepSync, part of the EIC Communities project, these stories offer a unique opportunity to connect with fellow members and innovators. By showcasing the challenges and successes of each project's journey, these stories present key moments and insights that can raise visibility, foster deeper understanding, and encourage collective knowledge exchange across communities.

As any quantum physicist will tell you, it's a world of uncertainty. So, when university physicist Kurt Stokbro swapped learning boards for circuit boards and left academia two decades ago, he knew he was stepping into the void of unpredictability. "I'm a quantum physicist by training," Kurt explains. "When I came to the company Sparrow Quantum as a tech investor, there was really exciting technology, but no funds to develop the hardware."

The promise of the Copenhagen-based company followed 15 years of deep research by Professor Peter Lodahl, Founder & Chief Quantum Officer of Sparrow Quantum, and his research group at the Niels Bohr Institute. They developed the world's first chip-based single-photon source: a device that allows independent photons to emerge that are essential particles for all things quantum, from computers to sensors and the weird world of quantum entanglement.

It's a deceptively simple goal: to produce one photon at a time, on demand, and with perfect consistency. But commercialising the photonic quantum chip technology that's notoriously unstable looked like a long and expensive nightmare. "Quantum is not something that comes out of a garage," says Kurt. "It's deep, basic research built over many years."

The solution arrived through the European Innovation Council (EIC) Accelerator grant, the EU programme designed to propel breakthrough technologies out of the start-up lab and into the commercial market. "It is a significant amount of money, so you can really do something with it. It was the ignition of the company, the spark for setting something in action." The funding led to the creation of the QTOOL project, allowing the fledgling firm to build laboratories, demonstrate proof of concept, and attract investors. Within a year, Sparrow raised €4 million in seed funding; later in 2025 came a €21.5 million Series A round, including €5 million in matching equity from the EIC. "Then the ball started really rolling," says Kurt. "Without the initial EIC Accelerator, there would be no Sparrow Quantum today."

Building the photon factory

The company's first task was to take the technology out of the academic lab and into a commercial one by making the chip available to other scientists using optical labs. That phase succeeded when Sparrow sold its chips to research groups such as the University of Vienna, which tested and later purchased them for ongoing work. "You make a product and then you send it out and test it outside your own lab, with an external source. I think that was a really clever thing and something that served us well," Kurt explains.

But the need for an optical lab set up was a limiting factor. The second, more ambitious phase was to make the system 'plug-and-play': fitting a standard 19-inch rack unit that could slot into a government, privately owned, or research-oriented supercomputing centre.

In a 2025 partnership with the UK's Orca Computing, Sparrow built and delivered the first prototype to the National Quantum Computing Centre (NQCC) testbeds: a £30m initiative to accelerate the development of quantum computing capabilities and infrastructure. "We have delivered the first prototype to the NQCC testbed in the UK, where our source is working together with their quantum computer," Kurt says.

It's a fine achievement in what is, after all, the United Nations' 2025 International Year of Quantum Science and Technology.

Wavelengths and roadblocks

For a story of such sudden success, the uncertain journey wasn't without major challenges. Sparrow's original single-photon sources emitted light at 950 nanometres that was perfect for laboratory testing but incompatible with the 1550 nanometre band used by the telecom industry.

The QTOOL team tried building an add-on module to shift the wavelength, but the solution proved unwieldy and costly. "It was practical for academic settings," says Kurt, "But the kind of commercial value was not high because it was very bulky, very expensive, the specs were not good enough."

Instead, the company set out to redesign the device to emit directly at around 1310 nanometres: a sweet spot between feasibility and function. "We found that making photon sources emit directly at 1310 nanometres was a good compromise—practical and valuable," Kurt explains.

The pivot meant rewriting parts of the original workplan, but here the EIC's flexibility proved invaluable when they applied, and were given time, to extend the project to overcome this hurdle. Kurt says the technical manager at EIC was understanding and he had key knowledge of the sector. "The EIC understood that we shouldn't do things just to tick boxes, but actions that made sense for the company. When we got the project, there were two employees; today, Peter and I co-lead a team of over forty."

Future Frontiers

Sparrow's next goal reaches even further into the quantum frontier: developing a commercial multi-photon entanglement source—something that doesn't yet exist. Entangled photons lie at the heart of quantum ultra-secure communication and computation, enabling the ghostly connections between seemingly unconnected particles that Einstein once called "spooky action at a distance."

If successful, Sparrow's next-generation source could power the second wave of quantum computing, linking qubits (the bits of a quantum computer) across distances and devices. Either way, markets predict that the three core pillars of quantum technology—computing, communication and sensing—will grow revenue from $4 billion in 2024 to as much as $72 billion by 2035.

2025 is the year of quantum science, and following that initial QTOOL project, the company's rise encapsulates what the EIC Accelerator aims to do: transform uncertain academic brilliance into more stable European industry. "That initial EIC support turned a good idea into an important European company, a star in the European kind of quantum sky."

Contacts:

Project coordinator: APRE

Stefania De Santi, desanti@apre.it

Communication Team: Fondazione ICONS

Cesar Giovanni Crisosto—cesar.crisosto@icons.it

Caterina Falcinelli—caterina.falcinelli@icons.it

Project website: https://deepsync.eu

LinkedIn: DEEPSYNC

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