Plessey Semiconductors is scaling its UK manufacturing capability and fueling the next generation of AI infrastructure
For years, the manufacturing strategy at Plessey focused on one question: How do you take microLED technology from innovation to commercial scale? Today, that work continues, while a second question is shaping the company’s next phase of growth: How do you build the manufacturing capabilities needed for the next generation of AI infrastructure?
For more than a decade, Plessey has built one of the UK’s most advanced vertically integrated microLED semiconductor capabilities. Now, that platform is being applied to optical interconnects, technology designed to address one of the biggest challenges facing next-generation AI infrastructure: moving increasingly vast volumes of data quickly, efficiently and with lower power consumption. This next phase of growth is shaping everything from capital investment and recruitment to process development and facility expansion.
Since Haylo Labs acquired Plessey, the company has recruited more than 80 people to date across technical, manufacturing and operational roles, while continuing to invest in its Plymouth manufacturing capability through new tools and expanded technical capability. It has also opened an Oxford office to support the growth of its Optical Interconnect business and broaden access to specialist engineering and commercial talent.
Thomas Abbott, Operations Director, stands at the center of that activity. After nearly 13 years at Plessey, he has guided the business through multiple stages of growth, with his current role overseeing manufacturing, engineering, facilities, and factory performance.
Since the Haylo acquisition, Plessey has grown not only its manufacturing footprint, but the expertise behind it. “We’ve installed new equipment, upgraded facilities, and strengthened our technical teams,” says Thomas. “We’ve onboarded new customers and partners. I’ve really enjoyed the cultural changes that came with it.”
A major advantage for Plessey is that these capabilities sit within one vertically integrated UK semiconductor business. The company can design, fabricate, test, and manufacture advanced photonic devices within its own facilities, rather than relying on multiple third-party foundries and outsourced partners. That gives Plessey greater control of its intellectual property and manufacturing roadmap, while enabling much faster iteration as products move from development towards commercial production.
That integrated structure is particularly powerful at the Plymouth site, where research, engineering and manufacturing work together rather than operating in silos. “The facility runs 24 hours a day, and our systems and processes support continuous engineering.” For Thomas, this creates faster learning cycles and a team accustomed to solving problems in real time. “Manufacturing gets easier because you’re used to change management and unexpected issues. We’re built to handle problems, so production flows more smoothly because we’re always ready to tackle challenges.”
This continuous mindset helps tackle one of the biggest challenges in semiconductor manufacturing: scaling technology without losing control of quality, yield, or consistency. Plessey has spent years refining microLED processes and now applies many of those lessons to optical interconnect development.
Thomas believes technology development and manufacturability need to happen in parallel rather than as separate stages. “Developing a technology and making it manufacturable are not sequential activities, they need to happen concurrently.” That integrated approach creates faster learning cycles, with manufacturing insight feeding directly back into development to improve yield, cost, and speed while shortening the path from innovation to production.
A lot of Plessey’s flexibility comes from its GaN-on-silicon platform. Originally designed for high power LEDs, the technology now forms the foundation for both display products and optical interconnect systems. “GaN-on-silicon lets us run larger substrates with improved performance. That’s a huge commercial advantage. It enables other key fabrication technologies like hybrid bonding, to be more effective. We’ve built up a lot of experience with it, and it’s no accident we’re using it for both displays and interconnects.”
Recent investments show a clear effort to bring critical expertise closer to the production line. One of the biggest additions in the past year is phosphide epitaxy capability. “Twelve months ago, we couldn’t grow our own red LEDs onsite. That’s now coming online. We believe in keeping everything in-house because it drives speed and learning. We did all this in the last year. It’s been challenging, but very rewarding.”
Plessey is investing now to make sure manufacturing constraints don’t limit future growth. “We’ll have more tooling coming online in the next few months to help remove bottlenecks in the fabrication plant. As development and manufacturing ramp up, we need capacity to keep up.”
Growth has brought new people into every part of the business, but not all that talent comes from outside. “We have a strong track record of developing people internally. Many operators become technicians, and technicians become engineers over time. That’s something I’m really proud of.” This internal growth goes hand in hand with recruiting for manufacturing, reliability, testing, device physics, and program management.
The blend of internal and external talent matters even more as Plessey broadens its optical interconnect work. The new Oxford office is part of a bigger shift in how Plessey builds its optical interconnect business. There’s a strong pool of talent across the M4 corridor, and many design, customer-facing, and technical roles don’t need to sit in Plymouth. “Oxford gives us access to those skills, while Plymouth stays at the heart of manufacturing.”
Managing multiple technology streams at once means you need a clear view of the whole business. Thomas’ approach is hands-on. He wants to know what’s happening in the factory and uses operational data to find constraints before they slow things down. “I’m a big fan of being on the shop floor, seeing what’s going on. If you balance velocity, effort, and engineering input, you can spot what’s slowing things down, whether it’s manpower, tooling, or something else.”
At the same time, the company’s strategic focus is expanding. Today, that operational discipline is also being applied to a major new growth opportunity in AI infrastructure. Plessey’s move into Optical Interconnects builds directly on the technology, intellectual property and manufacturing capability developed through its Display business. Many of the underlying semiconductor processes are already proven, giving Plessey a significant head start as it applies its microLED platform and manufacturing expertise to the rapidly growing AI infrastructure market.
For Plessey, Optical Interconnects are not a departure from what came before, but the next application of a semiconductor capability built over many years. The same expertise, processes and infrastructure developed for microLED displays are now being applied to a rapidly growing challenge in AI infrastructure. With research, design, fabrication, testing and manufacturing brought together within its UK operations, Plessey believes its ability to move quickly from innovation to scaled manufacturing will be a defining advantage. As Thomas puts it, “The objective stays the same: create an environment where new technologies can move from concept to production and scale when the market is ready.”
