French DeepTech Startup Lands Millions to Solve AI's Costly Photonics Bottleneck

Jan de Vries · 2026-09-22

There's a hidden cost inside the AI boom, and it's not just the electricity bills. It's happening at a microscopic level, inside the photonic chips that are becoming essential for faster computing. A French startup called Lightspring just got a major financial boost to tackle it. They've secured over $3.7 million to move their groundbreaking technology from the lab to the production line. This includes a $3.3 million Seed round and a $370,000 grant. The goal? To industrialize a process that could cut the cost of making these advanced chips in half. ### The Multi-Million Dollar Problem Here's the thing about photonic integrated circuits (PICs)—they're crucial for next-gen AI infrastructure. But making them is incredibly expensive. Surprisingly, the actual chip fabrication in a foundry is only about 20% of the total cost. The real budget-killer is the assembly and 'optical packaging'—the process of getting light in and out of the chip efficiently. That step alone eats up roughly 50% of the final price tag. It's a slow, finicky process done piece by piece, requiring super-precise alignment that's measured in micrometers. The result? Significant energy loss, low production yields, and no real standard. It's a bottleneck that's holding the whole industry back. ### A 3D Printing Solution for Light Lightspring, founded in Besançon, France, is attacking this problem head-on with a novel approach. They're using a form of 3D lithography—think of it like ultra-precise 3D printing at a microscopic scale—to build the optical interfaces directly onto the chip itself. Instead of manually aligning tiny parts, they 'print' structures like microlenses and waveguides right where they're needed. It turns a complex assembly job into a single, programmable manufacturing step. - **Radically Faster Design:** What used to take several months for custom packaging can now be done in under two weeks. - **Major Performance Boost:** They're targeting coupling losses below 0.5 dB per interface, a huge improvement over the typical 2–3 dB loss from current methods. - **Eliminates Manual Labor:** The need for painstaking active alignment is removed entirely. ### What the Backers Are Saying The funding round was led by Atlantic and OVNI Capital, with other investors joining in. Quentin Calleja, a Principal at Atlantic, put it plainly: "Photonics is scaling into AI infrastructure fast, but optical packaging remains a slow and expensive step. Lightspring has developed a technology that finally makes it scalable." He added, "We back teams with the potential to become the leaders of categories that don't exist yet, and Lightspring is definitely one of them." ### From Lab Curiosity to Industry Standard For Lightspring's CEO and co-founder, Grégoire Bonnat, this funding is about validation and velocity. "The whole industry is working on making photonic chips faster," he says, "yet light still loses most of its energy the moment it enters or leaves the device. We decided to attack that specific problem." Their core innovation isn't just the fabrication technique. It's the design layer—the first Process Design Kit (PDK) dedicated to 3D optical coupling. This software and recipe package is what could allow their method to become a new standard. The technology sprang from EU-funded research, showing how European deep tech is pushing the envelope. Now, with this multi-million dollar vote of confidence, Lightspring is aiming to turn their lab breakthrough into a fundamental building block for the future of computing. It's a reminder that sometimes, the biggest leaps come from solving the smallest, most expensive problems.