Relativity Networks raises $22M for hollow-core fiber to speed data centers
Relativity Networks raises $22M and secures a $40M hyperscaler order for hollow-core fiber that speeds data center links by 30%.
The funding round was drawn by Rhapsody Venture Partners, Bell Ventures Inc., and Faster Than Glass LLC, among others. A SAFE note, which converts into shares when the company raises its first priced round, is a standard method for pre-seed and seed rounds.
Relativity Networks deals in hollow-core fiber, a rarely deployed technology that transmits data 30% faster than conventional fiber. Traditional fiber sends light through fiber-optic glass, while hollow-core fiber transmits the same light through a vacuum chamber in the center of the line, bringing it far closer to the theoretical limit of light speed.
The difference is a matter of microseconds. CEO Jason Eisenholz estimates a signal takes roughly five microseconds to travel one kilometer in conventional fiber, and about three and a half microseconds with hollow-core.
As AI compute has scaled, so has the physical distance between GPUs, with data center campuses now often sprawling across hundreds of acres and dozens of buildings. Eisenholz sees a particular opportunity for multi-campus deployments, in which pre-existing data centers are knit together to operate as a single unit. “The largest systems are distributing the compute across multiple campuses to reach the power that exists,” he told TechCrunch. “They’re moving to where the warm shell is, but they still need to operate as one synchronized machine.”
Data center developers are expected to spend as much as $4 trillion by the end of the decade, but their choices are already heavily constrained by political and power-grid considerations. Faster fiber could partially ease that spatial logic, since cutting latency by 30% means developers can span 30% larger distances before latency becomes a problem.
“The first era of AI optimized for compute,” Eisenholz said. “It was GPU, GPU, GPU. The second era optimized the networking inside the data center to take advantage of that compute. The third era that we see coming is optimizing the geography.”