Lightmatter builds networking equipment that uses light instead of electricity to connect AI chips across a data center, delivering dramatically more bandwidth with less energy. Their technology can link chips together at speeds previously only possible within a single processor, removing the networking bottleneck that slows down large AI systems. Lightmatter's Passage interconnect is capable of connecting chips across an entire data center with the bandwidth density previously only possible within a single chip. Their programmable photonic technology can dynamically reconfigure data pathways, unlike fixed electrical connections.

As AI clusters scale to hundreds of thousands of GPUs, the network connecting them becomes the primary bottleneck; Lightmatter's photonic fabric directly solves this by providing orders of magnitude more bandwidth at lower power.

Lightmatter raised $400M in 2025, reaching a $4.4B valuation, and has been deepening partnerships with major AI chip and cloud companies to integrate its photonic interconnect technology into next-generation data center architectures.