QLUSTER · Project

Scalable Entangled-Photon Sources for Quantum Computing and Secure Networks

digitalPrototypeTRL 3Thin data (2/5)

Imagine you need thousands of tiny particles of light all perfectly linked together — like a massive team where every member instantly knows what the others are doing. Right now, creating these linked photons is like flipping coins and hoping they all land heads — it works for a few, but falls apart at scale. QLUSTER figured out how to use a single quantum dot (a nanoscale semiconductor) as a deterministic "photon factory" that reliably stamps out streams of entangled photons. This is the missing ingredient for building practical quantum computers and hack-proof communication networks.

By the numbers

>65%

Target brightness for single photon source

< 10⁻³

Target photon purity g2(0)

500 MHz

Target repetition rate for photon generation

Partner organizations across 7 countries

Total project deliverables

The business problem

What needed solving

Current methods for generating entangled photons are probabilistic and inefficient — they work for small numbers but fail completely when you try to scale up. This is the core bottleneck preventing practical quantum computers and high-rate quantum communication networks from becoming reality. Without a reliable, scalable source of many entangled photons, the entire photonic quantum technology industry remains stuck at small-scale demonstrations.

The solution

What was built

QLUSTER produced 15 deliverables including an experimental demonstration of core graph state generation and an optimized single-photon source from semiconductor quantum dots with specific performance targets: brightness above 65%, photon purity g2(0) below 10⁻³, and 500 MHz repetition rate.

Audience

Who needs this

Quantum computing hardware companies building photonic processorsTelecom operators developing quantum key distribution networksPhotonics manufacturers producing quantum light source componentsDefense and intelligence agencies investing in quantum-secure communicationsCloud computing providers exploring quantum computing as a service

Business applications

Who can put this to work

Quantum Computing Hardware

enterprise

Target: Companies developing photonic quantum processors

If you are a quantum hardware company struggling with the bottleneck of generating enough entangled photons reliably — QLUSTER developed a deterministic single-photon source using semiconductor quantum dots in optical micro-cavities, targeting brightness above 65%, purity below 10⁻³ in g2(0), and a 500 MHz repetition rate. This could replace your current probabilistic photon sources and let you scale to many-photon entanglement without exponential loss.

Cybersecurity and Telecommunications

enterprise

Target: Telecom operators and cybersecurity firms building quantum key distribution networks

If you are a telecom provider investing in quantum-secure communication but limited by the low rate and unreliability of current entangled-photon sources — QLUSTER's technology produces entangled photons deterministically at up to 500 MHz repetition rate. This means higher key distribution rates and more practical quantum network deployments across your infrastructure.

Semiconductor and Photonics Manufacturing

mid-size

Target: Manufacturers of quantum dot devices and photonic components

If you are a photonics manufacturer looking for the next generation of quantum light source products — QLUSTER demonstrated core graph state generation and optimized single-photon sources from semiconductor quantum dots with specific benchmarks (brightness >65%, 500 MHz). These specifications provide a concrete product roadmap for commercial quantum photon source modules.

Frequently asked

Quick answers

What would a commercial product based on this technology cost?

No pricing data is available from the project. This is early-stage research from a purely academic consortium with no industrial partners. Commercial cost estimates would depend on quantum dot fabrication and micro-cavity integration costs, which are not addressed in the project deliverables.

Can this technology work at industrial scale?

The project targeted specific performance benchmarks — brightness above 65%, photon purity g2(0) below 10⁻³, and 500 MHz repetition rate — which represent significant steps toward scalability. However, QLUSTER was a research project with 7 academic partners and no industry involvement, so industrial-scale manufacturing was not within scope.

What is the IP situation and how could a company license this?

As a publicly funded RIA project under Horizon 2020 FET Open, IP generated typically belongs to the consortium partners (5 universities and 2 research organizations across 7 countries). Companies interested in licensing should contact Universiteit Leiden as coordinator. Standard EU grant IP rules apply.

How close is this to a real product?

QLUSTER delivered a demonstration of core graph state production and an optimized single-photon source with defined benchmarks. This places the technology at experimental proof-of-concept stage. Significant engineering and industrial development would be needed before a commercial product emerges.

What infrastructure would be needed to integrate this technology?

Based on available project data, the technology relies on semiconductor quantum dots coupled to optical micro-cavities operating under cryogenic conditions. Integration into existing photonic systems would require specialized fabrication facilities and low-temperature infrastructure.

Are there regulatory considerations for quantum technologies?

Quantum technologies are subject to evolving export control regulations in the EU and internationally, particularly for encryption and dual-use applications. Based on available project data, QLUSTER focused on fundamental research, but any commercial deployment would need to address these regulatory frameworks.

Consortium

Who built it

QLUSTER brought together 7 partners from 7 countries (CH, DE, EL, FR, IL, NL, UK), coordinated by Universiteit Leiden in the Netherlands. The consortium is entirely academic — 5 universities and 2 research organizations with zero industrial partners and zero SMEs. This is typical for a FET Open project tackling fundamental science at the frontier of quantum physics. For a business buyer, this means the technology is still firmly in the research domain: there is deep scientific expertise but no built-in pathway to commercialization. Any company wanting to use these results would need to invest in technology transfer and engineering development.

UNIVERSITEIT LEIDENCoordinator · NL
THE CHANCELLOR MASTERS AND SCHOLARS OF THE UNIVERSITY OF CAMBRIDGEparticipant · UK
UNIVERSITAT BASELparticipant · CH
TECHNISCHE UNIVERSITAET MUENCHENparticipant · DE
IDRYMA TECHNOLOGIAS KAI EREVNASparticipant · EL
THE HEBREW UNIVERSITY OF JERUSALEMparticipant · IL
CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE CNRSparticipant · FR

How to reach the team

Universiteit Leiden (Netherlands) coordinated QLUSTER. Contact their technology transfer office or the physics department for licensing inquiries.

Order a report on this consortium See UNIVERSITEIT LEIDEN profile →

Next steps

Talk to the team behind this work.

Want to explore how deterministic entangled-photon sources could fit your quantum technology roadmap? SciTransfer can connect you with the QLUSTER research team and help assess commercial potential.

Order a report on this topic More in Digital & ICT