Analysis
Salience Labs has closed an oversubscribed $125 million Series B to scale photonic chips for AI datacenter networking, the Oxford spinout announced on October 14. Bullhound Capital led the round, with new investors AMD Ventures, Intel Capital, SBI Group, Hudson River Trading and the British Business Bank, alongside existing backers Applied Ventures, Oxford Science Enterprises, Cambridge Innovation Capital and Silicon Catalyst Ventures.
The pitch: optical switching for GPU clusters
Salience Labs, founded in 2021 out of more than a decade of photonics research at Oxford and the University of Münster, builds optical circuit switching (OCS) technology -- an all-optical switch designed to connect thousands of GPUs across multiple server racks for scale-up networking, the kind of interconnect that determines how efficiently a GPU cluster can actually be used rather than just how many chips a company buys. The company demoed a 64-port all-optical photonic switch at the ECOC conference this year and plans 128- and 256-port versions next.
“The company demoed a 64-port all-optical photonic switch at the ECOC conference this year and plans 128- and 256-port versions next.”
Why investors are chasing interconnect, not just chips
AMD Ventures and Intel Capital both joining as new investors signals that the two biggest Nvidia alternatives want exposure to the networking layer regardless of whose GPUs end up in a given data center -- a hedge against picking the wrong chip winner. Dell'Oro Group, cited in the funding announcement, forecasts cumulative spending on AI back-end datacenter switches will approach $1 trillion between 2026 and 2030, with scale-up networking expected to exceed half that market by 2030. That forecast is the real reason photonics-for-AI has become a crowded category alongside Ayar Labs and Lightmatter, both of which have also raised large rounds on a similar thesis that electrical interconnects can't keep pace with GPU cluster growth.
Salience says the money funds wider OCS deployment, volume manufacturing work with Keysight Technologies and Tower Semiconductor, and a second U.S. office in Silicon Valley. The company did not disclose a valuation.
What to watch: whether Salience's optical switches actually ship into production GPU clusters at scale in 2026, or whether -- like several photonics startups before it -- the technology stays in demo and pilot mode while electrical interconnect vendors keep closing the efficiency gap.