Startup raises $22M for faster data-center fiber

Relativity Networks raised $22 million in SAFE note funding from Rhapsody Venture Partners, Bell Ventures, and Faster Than Glass, plus a separate $40 million follow-on order from an unnamed hyperscaler, to build out hollow-core fiber for data-center networking. Unlike conventional fiber, which transmits light through glass, hollow-core fiber sends it through a vacuum-like core, cutting transmission time from roughly 5 microseconds per kilometer to about 3.5, a roughly 50% reduction.

CEO Jason Eichenholz described the problem the technology targets:

“The largest systems are distributing the compute across multiple campuses to reach the power that exists.”

As AI training and inference workloads increasingly span multiple data-center campuses to find enough power, the extra latency between sites becomes a real constraint on treating them as one synchronized system. The lower-latency fiber lets those campuses sit up to 50% farther apart before that constraint kicks in.

What it means for you

This is deep infrastructure, not a tool you’ll touch directly, but it’s a useful data point on where AI capacity bottlenecks are shifting: as compute buildouts run into local power limits, multi-campus distribution and the networking that stitches those campuses together become as important as the chips themselves. It’s part of the same physical-infrastructure wave as Nvidia’s $105B financing for OpenAI’s Ohio data center and Nvidia’s $500B financing push with Wall Street, where power and distance, not GPU supply, are becoming the binding constraint on how fast AI compute can scale.