Prysmian and Relativity Networks Deploy Highest-Density Hollow Core Fiber Cable to Date

Italian optical cable manufacturer Prysmian and U.S.-based Relativity Networks have successfully deployed what they describe as the highest-density hollow-core fiber cable yet produced, marking a significant step toward commercializing next-generation optical infrastructure for AI and data center networks. The deployment builds on a partnership signed between the two companies last year for the mass production of hollow-core optical fiber (HCF) and cabling.

Testing took place at Dura-Line’s flagship test facility in Clinton, Tennessee, with Prysmian collaborating with Dura-Line, a manufacturer of high-density polyethylene (HDPE) conduit solutions. The tests confirmed the reliable installation of a high-density cable incorporating Relativity Networks' ChronoCore hollow core fibers at jetting speeds of up to 350 feet per minute. According to Prysmian, the demonstration was critical in proving that the technology is ready for real-world deployment and represents a forward step for the development of AI optical infrastructure and data center networks.

The cable is built on Prysmian’s Sirocco architecture and integrates Relativity Networks' ChronoCore hollow core fibers. Prysmian noted that the cable "delivers the expected optical performance while supporting the development of next-generation low-latency data center infrastructure." Hollow core fiber is widely considered a transformational upgrade from traditional fiber because of its design: an air-filled center channel surrounded by a ring of glass tubes, resembling a honeycomb pattern. This design enables higher capacity with minimized chromatic dispersion, while light travels significantly faster compared to conventional fiber.

Traditional fiber-optic cables have typically limited data centers to within 60 kilometers (37 miles) of power providers or to each other due to latency constraints. However, HCF extends this range to 90 kilometers (56 miles). The technology’s extended reach, lower latency, and higher bandwidth are seen as crucial for hyperscale data center operators, especially those supporting distributed AI workloads. Jason Eichenholz, founder and CEO of Relativity Networks, has previously told DCD that there is huge demand for this technology from hyperscalers, which was a key driver behind the Prysmian-Relativity partnership last year.

“This milestone comes just 15 months after Prysmian’s partnership with Relativity Networks to industrialize hollow core fiber—and reflects Prysmian’s long-standing leadership in innovation,” said Srinivas Siripurapu, chief innovation and sustainability officer at Prysmian. “We worked closely with Relativity Networks and Dura-Line to achieve this important industry milestone to showcase the scalability and technological readiness of this innovative digital infrastructure.” Rodrigo Amezcua Correa, CTO of Relativity Networks, added: “A breakthrough fiber technology only matters if it can be manufactured, cabled, and deployed at scale - and this milestone proves that it can. Seeing ChronoCore HCF produced and installed while delivering the performance it was designed for – to enable the next generation of distributed AI – marks the transition from innovation to infrastructure.”

Prysmian also provided an update on its scaling efforts, stating that it is already ramping up production of Relativity Networks' hollow core fiber, including investments in its Eindhoven facility in the Netherlands. Meanwhile, its plant in Claremont, North Carolina, has successfully manufactured a cable containing 24 hollow core fibers in a 10-millimeter diameter cable. Separately, Prysmian announced this week it had signed a €5.5 billion ($6.29 billion) agreement with Koch-owned Molex to supply optical cables for deployment inside data centers. The company said that deal, along with other new commercial initiatives with hyperscalers and data center infrastructure providers, is expected to generate an additional cumulative value of more than €10 billion ($11.41 billion) on an incremental basis through 2035, compared to the 2025 baseline.