Altman-backed silicon-photonics startup Volantis raises $88M Series A to push past the memory wall
On October 5, Volantis announced an $88M Series A led by Lachy Groom with Abstract Ventures, replacing electrical interconnects with silicon photonics interposers and targeting 10TB+ memory per package.
On October 5, San Francisco chip startup Volantis announced an $88M Series A round. The round is led by Lachy Groom with Abstract Ventures co-leading; Sam Altman is an early backer. Volantis is tackling a fundamentally physical problem: HBM must sit close to the compute die to keep power down and signal integrity intact, so capacity and bandwidth are bottlenecked by the chip shoreline (AMD MI455X caps at around 432GB).
Volantis replaces electrical interconnects with photonic waveguides in a photonic interposer, letting memory sit several centimeters away. The company claims a single large package can host 10TB+ of memory with 240TB/s of bandwidth — enough to serve a 20-trillion-parameter model at 10,000 tokens per second per user. The technical path goes wide and efficient: many slow links instead of fewer fast ones, with micro-VCSELs integrated directly into the interposer rather than relying on external lasers.
CEO Tapa Ghosh emphasizes that Volantis does not license IP but delivers complete systems, targeting a prototype in 12-18 months. Silicon photonic interposers are not a new idea — Lightmatter and Celestial AI have both attempted it, and Marvall acquired Celestial AI for $5.5B. Whether Volantis can actually ramp into high-volume production remains the biggest open question.