Relativity Networks raises $22M for hollow-core fiber in data centers
Original: Relativity Networks raises $22 million to bring a faster kind of fiber to data centers
Why This Matters
Hollow-core fiber could reshape data center geography as AI clusters grow to multi-campus scale.
Relativity Networks announced $22 million in SAFE note funding led by Rhapsody Venture Partners, Bell Ventures, and Faster Than Glass LLC, to deploy hollow-core fiber technology that transmits data 30% faster than conventional fiber, targeting AI data center campuses.
Relativity Networks announced $22 million in SAFE note funding on August 19, 2026, from investors including Rhapsody Venture Partners, Bell Ventures Inc., and Faster Than Glass LLC. The company also secured a $40 million follow-on order from an unnamed hyperscaler. The startup specializes in hollow-core fiber, a technology that transmits light through a vacuum chamber rather than glass, reducing latency from approximately five microseconds per kilometer to around 3.5 microseconds — a 30% improvement over conventional fiber. CEO Jason Eisenholz explains that as AI compute scales across large campuses and multi-site deployments, fiber latency has become a meaningful constraint. With hollow-core fiber, data center developers can effectively extend the viable distance between GPU clusters by 30%, enabling new multi-campus configurations. Eisenholz framed the trend as a third era of AI infrastructure: 'The first era optimized for compute. The second era optimized the networking inside the data center. The third era that we see coming is optimizing the geography.' Data center spending is projected to reach as much as $4 trillion by the end of the decade.