IQE and Quintessent create quantum dot epitaxial wafer supply chain for AI optical interconnects

IQE is a global supplier of compound semiconductor wafers and advanced material solutions headquartered in Cardiff, U.K., and earlier this year they announced a partnership with Quintessent, a Santa Barbara, CA-based company that specializes in optical connectivity solutions to scale computing and artificial intelligence (AI), to create a quantum dot epitaxial wafer supply chain to help meet the demand for AI data centers’ transition from copper to optical interconnects.

Laser Focus World: What inspired your work with quantum dot lasers?

Mark Furlong: I’ve spent much of my career in compound semiconductors, and quantum dot lasers have always stood out as one of those technologies with the potential to solve very specific, long-standing problems—particularly around performance and energy efficiency within demanding environments.

What makes quantum dots so interesting is how they behave at the atomic level. Their discrete energy states give you more stable operation, lower threshold currents, and improved temperature performance compared to quantum well-based lasers. This translates into real-world benefits like lower power consumption, extended device lifetimes, and tighter control over wavelength—all of which are critical for AI-driven data center applications.

The recent shift to silicon photonics has created a natural entry point for this technology. The demands for bandwidth, latency, and energy efficiency are growing quickly. Quantum dot lasers fit well into that evolution because they offer a reliable, scalable light source that performs under pressure.

LFW: How is IQE differentiating itself? And why partner with Quintessent?

Furlong: IQE’s strength has always been in scaling advanced semiconductor materials from lab to fab. We don’t just manufacture epitaxial wafers, we engineer them to meet the most exacting device-level requirements.

Our partnership with Quintessent is a good example of this. We’ve been working together for more than a decade to mature quantum dot laser technology, starting from fundamental research at the University of California, Santa Barbara (UCSB) through to commercial-scale production. Quintessent brings deep intellectual property (IP) and design expertise in heterogeneous silicon photonics. IQE brings process control, volume manufacturing capability, and materials integration across large-format gallium arsenide (GaAs) platforms.

LFW: How’s demand for quantum dot laser epitaxial wafers?

Furlong: We’re still early in terms of market adoption, but the demand signals are strong. Data center operators and chip designers are looking ahead to next-generation optical interconnects that can meet AI workload requirements without creating energy bottlenecks.

Traditional laser sources are reaching their limits in terms of efficiency and stability. Quantum dot-based devices offer a path forward, and it’s starting to translate into more interest and more engagement upstream in the supply chain. The initial order we’ve announced with Quintessent is just the start. We’re already in conversations with other partners looking at similar architectures.

LFW: Any manufacturing challenges/surprises?

Furlong: The main challenge is consistency—translating a quantum dot design from the research environment into a high-yield, high-uniformity production process. Quantum dots are sensitive to growth conditions, so building a stable, repeatable platform on 6-inch GaAs substrates was a significant achievement. IQE’s know-how scaling advanced photonics structures into high-volume production was invaluable for this step.

What helped us succeed is the close collaboration between our process engineering teams and Quintessent’s device teams. We weren’t operating in isolation. This alignment has been key to hitting the right performance metrics, especially around lasing thresholds and linewidth.

LFW: How will building out the quantum dot laser epitaxial wafer supply chain enable/speed AI optical interconnect adoption?

Furlong: Optical interconnects are a critical piece of the AI infrastructure puzzle. As compute workloads grow, copper simply can’t keep up—electrically or thermally. Silicon photonics is the future, but it needs efficient, reliable laser sources to scale.

By building a commercial-ready supply chain for quantum dot laser epitaxy, we’re helping de-risk adoption. We’re giving system architects confidence that the materials are there, the performance is proven, and the volumes can scale.

That’s the real unlock. Once that foundation is in place, it becomes much easier for the rest of the ecosystem to move forward—from device integration to packaging to deployment.

LFW: Timeline?

Furlong: We’re already delivering production wafers to Quintessent and will continue shipments through 2025. From our side, the platform is ready. We’ve proven performance, we’ve demonstrated yield, and we’re now scaling to support broader adoption.

The focus now is continuing to refine the process, support customer-specific requirements, and work with the broader industry to align on standards and integration strategies. It’s a fast-moving space, and we’re positioned well to support the growth we expect to see within the next 12 to 24 months.

About Mark Furlong: Mark J. Furlong is IQE’s chief revenue officer. His career in compound semiconductors commenced in the late 1990s at Epitaxial Products International following which he held various commercial and technical marketing roles within IQE, which included responsibility for APAC business development. He previously worked for the CNRS in Paris on the development of semiconductor materials for next-generation solar cell technology and was awarded an Industrial Fellowship from the Royal Society in London to pursue this work. He holds a Ph.D. degree in semiconductor science and technology from the University of Bath and a B.Sc. (Hons.) degree in Chemistry from the University of London. He also holds a Diploma in Management with Distinction from the Open University, U.K.