Salience Labs has closed an oversubscribed $125M Series B to scale all-optical circuit switching for AI datacenters, the Oxford company said on October 14.
Bullhound Capital led the round. AMD Ventures, Intel Capital, SBI Group, Hudson River Trading and the British Business Bank joined, alongside existing backers Applied Ventures, Oxford Science Enterprises and Cambridge Innovation Capital.
The company builds switching silicon that routes traffic between accelerators entirely in the optical domain. Its pitch is that electrical switches become a latency, power and reliability bottleneck once a cluster spans thousands of GPUs.
Proceeds will fund volume manufacturing and a larger US presence, with a Silicon Valley expansion planned. Principal Callum Stewart of Bullhound joins the board.
The raise lands in a crowded photonics cycle. Foundries including TSMC, Tower and GlobalFoundries have all pushed silicon photonics into volume production this year, and co-packaged optics has moved from research demos to production planning across the industry.
Whether optical switching displaces established electrical fabrics at rack scale is still unresolved, but the investor list suggests the strategic buyers see a real window.
