News: Optoelectronics
27 March 2025
CSA Catapult–Vector Photonics–Phlux consortium gains Innovate UK funding for QUDITS2 quantum communication project
Compound Semiconductor Applications (CSA) Catapult is part of a consortium that is one of the winners of the Quantum Missions pilot competition, securing a share of £12m of funding from government agency Innovate UK. The collaboration brings together Vector Photonics Ltd (spun off from Scotland’s University of Glasgow in 2020), Sheffield University spin-off Phlux Technology —which designs and manufactures 1550nm avalanche photodiode (APD) infrared sensors — and the University of Bristol, alongside the Catapult’s expertise.
Established in 2018 by Innovate UK, CSA Catapult is a not-for-profit center of excellence that specializes in the measurement, characterization, integration and validation of compound semiconductor technology spanning power electronics, advanced packaging, radio frequency and microwave, and photonics applications.
The new QUDITS2 initiative aims to accelerate the development of quantum computing (QC) and quantum networks (QN) by overcoming barriers to commercialization — leveraging capabilities already proven by CSA Catapult’s earlier feasibility study QUDITS, delivered in 2024.
The project will build the demonstrator within a year and test the capability in the CSA Catapult’s telecoms testbed, while working to create a manufacturing roadmap — ultimately seeking to have completed systems ready for market 1–2 years from the project-end. Building on this, the QUDITS2 consortium will now seek to create a prototype, or hardware demonstrator platform, up to technology readiness level (TRL) 5.
Quantum networks
The future quantum internet will be defined by speed, energy efficiency and security and offers revolutionary possibilities, says CSA Catapult. As quantum computers become more powerful, sensitive data could be quickly intercepted and compromised by bad actors. Sophisticated encryption enabled by quantum key distribution (QKD) offers a solution — but these fast, secure communications links will rely on novel photonics technology, which QUDITS2 will demonstrate.
Such advances in quantum could lead to game-changing computing power, with the machines capable of performing beyond today’s most advanced supercomputers, potentially leading to breakthroughs in medicine and in the fields of AI and finance.
Qubits to qudits
During the initial feasibility study (QUDITS), CSA Catapult’s research showed the possibility of moving from using qubits to qudits — higher-dimensional states of quantum information that can carry more information. Unlocking this capability could create a disruptive and cutting-edge communications system, created using commercially available components within a sovereign UK supply chain.
The study demonstrated in the lab that using properties of light such as its orbital angular momentum (OAM) could lead to the development of commercial systems.
New commercial applications
The QUDITS2 consortium also aims to show a commercially feasible quantum communications system with real-world potential to advance future telecoms.
By bringing in commercially available capabilities from across the supply chain, QUDITS2 will show the hardware’s viability and its ability to be manufactured at comparatively lower cost. The system will make use of existing photonic crystal surface-emitting lasers (PCSELs) and low-noise avalanche photodiodes (APDs), which can operate at optical communications wavelengths.
PCSELs from Vector Photonics are high-speed, low-cost systems that bring considerable advantages over other types of lasers used in OAM systems. Phlux Technology has developed a far more sensitive low-noise detector technology, while the University of Bristol offers a novel metasurface able to increase yield and the output of the PCSEL lasers that are used.
The key enabler in QUDITS2 is the use of miniature phase plates with the PCELs, so the design size can be compacted and costs reduced.
Combined with the expertise in quantum commercialization from CSA Catapult, it is reckoned that QUDITS2 could demonstrate large commercial benefit, with an estimated return on investment (ROI) of 75 times on public funding investment, while opening the door to making the UK a quantum communications pioneer.
“This project will look to demonstrate a qudit-based communication system implemented through photonics and the manipulation of the orbital angular momentum state,” says Joe Gannicliffe, head of photonics and RF at CSA Catapult. “Qudits allow information to be transferred over multiple levels compared to qubits, which are the quantum analogy to a standard bit and limited to two levels. These additional states mean more information can be carried over the same channel, increasing the capacity of optical links,” he adds. “The Catapult is very pleased to continue working with key partners in Phlux, Vector Photonics and Bristol University in taking this technology to the next stage.”
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