Relativity Networks raised $22 million in a SAFE note round led by Rhapsody Venture Partners and Bell Ventures, with additional backing from Faster Than Glass LLC. The company also locked in a $40 million follow-on order from an unnamed hyperscaler. Its technology replaces conventional fiber with hollow-core fiber, which transmits light through a vacuum to cut latency by roughly 30%.
CEO Jason Eisenholz says the speed gain shaves about 1.5 microseconds per kilometer, reducing a one-kilometer signal trip from five to three and a half microseconds. That difference matters as data centers sprawl across hundreds of acres and multiple buildings, especially for multi-campus setups that must act as a single synchronized machine.
Eisenholz argues the latency drop lets developers expand data center footprints by about 30% before hitting latency limits. He frames it as the next phase of AI infrastructure: after optimizing compute and internal networking, the industry now targets geography. The company sees its fiber as a way to partially bypass political and power-grid constraints that limit where data centers can be built.
