Relativity Networks has raised $22M in SAFE funding to push hollow-core fiber into AI data centers, betting that light speed itself becomes a bottleneck as compute sprawls across campuses.
Rhapsody Venture Partners, Bell Ventures and Faster Than Glass LLC joined the round. The company also locked in a $40M follow-on order from an unnamed hyperscaler.
Hollow-core fiber transmits light through a vacuum channel instead of glass, cutting signal travel from about five microseconds per kilometer to three and a half. CEO Jason Eichenholz says the 50% latency reduction lets developers spread systems 50% further before timing becomes a problem.
That matters as data center campuses grow to hundreds of acres and multi-campus deployments knit older facilities into single synchronized machines. “The first era of AI optimized for compute,” Eichenholz says. “The second era optimized the networking. The third era that we see coming is optimizing the geography.”
Data center developers are expected to spend as much as $4T by the end of the decade, and AI workloads are pushing interconnect upgrades. Relativity is a small player attacking an infrastructure problem buyers notice once latency starts hurting training runs and inference.
The company positions its technology as a way to reach existing power and warm shells while still operating as one machine.
