Besançon-based Lightspring raises over €3.5 million to industrialise photonic chip packaging

Lightspring, a DeepTech startup based in Besançon, France, has successfully raised €3.1 million in a Seed round to commercialize photonic chip packaging. The funding was led by Atlantic and OVNI Capital, with contributions from Concept Ventures, Ixcore, Plug and Play Ventures, and industry business angels. The company has also received a €350k grant from France's national DeepTech innovation competition, i-Lab.

This financing brings Lightspring's total dilutive and non-dilutive funding to over €3.5 million, allowing the company to transition its 3D optical coupling process from lab to production.

Photonics is rapidly expanding into AI infrastructure, but optical packaging remains a costly and time-consuming step. Lightspring has developed a technology that aims to make this process scalable. By integrating photonic packaging directly into the chip fabrication, the company claims to have reduced optical packaging's cost from half to a programmable manufacturing step.

Photonic packaging currently accounts for half the cost of a photonic chip, and fibre-to-chip coupling is still done part by part via micrometre-scale active alignment, resulting in significant optical loss, low throughput, and low yield.

Lightspring's approach uses 3D lithography (two-photon polymerisation) to fabricate optical coupling structures such as microlenses, 3D waveguides, and beam-shaping elements directly on the chip. This single process step eliminates the need for precision pre-alignment, resulting in lower optical loss, higher throughput, and higher yield.

The company's core intellectual property lies in the design layer, which includes the first Process Design Kit (PDK) for 3D optical coupling, along with software-driven design tools and qualified fabrication recipes. The technology originates from research at the FEMTO-ST Institute in Besançon, a leading centre in optics and micro-nanotechnology.

The company plans to use the raised capital to further develop the PDK and design tools, hire new talent in microfabrication, optical characterisation, and photonic circuit design, and collaborate with industrial partners on a co-packaged optics roadmap for AI infrastructure. Lightspring aims to scale its fabrication platform and qualify the process under industrial conditions.