CScale raises $145M for AI data center optical interconnect technology

CScale announced its emergence from stealth today with $145 million in Series C funding to develop optical interconnect technology for gigawatt-scale AI data centers. The round brings the company's total funding to $188 million.

The startup focuses on the high-bandwidth, ultra-low-latency connections required to link thousands of accelerators across dozens of racks into a single, cohesive system. As AI data centers scale to gigawatt class by the end of the decade, these interconnections become critical infrastructure.

CScale's approach emphasizes system reliability. At the scale of hundreds of thousands of accelerators, rare individual failures become continuous fleet-level problems that degrade performance unless contained. The company is architecting its interconnect to isolate optical failures without interrupting compute operations.

"As AI scale-up domains extend across dozens of racks, optical interconnect becomes essential," said Martin Lund, CEO of CScale. "At that scale, reliable, predictable communication is fundamental to system economics. We're designing the interconnect for continuity. Lasers will fail. Compute shouldn't."

Lund previously led Cisco's Common Hardware Group, overseeing silicon, hardware systems, and optics including Silicon One. He also built Broadcom's switching business into a billion-dollar franchise and held senior roles at Microsoft and Cadence.

The Series C round was co-led by Atreides Management and Premji Invest, with participation from Sutter Hill Ventures and Maverick Capital. Nvidia and Intel Capital joined as CScale's first strategic investors. The Palo Alto-based company has 85 employees.

CScale was founded in 2023 by CTO Sanjai Kohli, who co-founded SiRF and later founded Inovi, acquired by Facebook in 2014. Kohli received the 2010 European Inventor Award for work bringing GPS to the mass market.