Inside Hollow-Core Fiber: Why Latency Just Got 30% Faster

Light Travels Faster Through Air Than Glass—and That's About to Matter

Your data center's fiber cables are already moving data at nearly the speed of light. But they're slowing down anyway. <cite index="1-2">The networks being built for AI and hyperscale computing are exposing the physical limits of conventional fiber.</cite> This constraint just triggered a major funding sprint: <cite index="5-2">Relativity Networks has completed a $6.1 million seed funding round, bringing its total financing to $10.7 million</cite>, with additional capital rounds following as the company ramps production.

Relative to previous fiber architectures, the technology behind Relativity's push is simple but radical. <cite index="6-5,6-6">Relativity Networks is a next-gen hollow-core fiber (HCF) provider that increases the speed of data transmission in fiber optics. By replacing glass with air, we created technology to move data nearly 50% faster and farther to address the growing demands of data centers and their enormous power requirements.</cite> This isn't theoretical—it's being deployed now.

The Physics: Why Air Changes Everything

<cite index="9-9">Light moves faster through air than through silica, and since fiber-optic cables transmit data using light waves, those that feature hollow cores can move information more quickly than traditional fiber-optic networks.</cite> The speed difference is quantifiable: <cite index="11-3,11-4,11-5">Light travels at about 200,000 km/s through glass. In hollow-core fiber, where light travels in a vacuum, speeds approach 300,000 km/s. That's a 40% increase—an essential advantage in environments where every microsecond counts.</cite>

For practical applications, this translates to measurable latency reductions. <cite index="22-3,22-4">Hollow Core Fiber (HCF) replaces the traditional solid glass core of optical fiber with an air-filled channel. This allows light to travel faster and reduces network latency by up to 30–35% per kilometer.</cite> In data center interconnect scenarios, that compounds quickly.

The second benefit is range. <cite index="4-9">Traditional fiber-optic cables have typically limited data centers to within 60 kilometers (37 miles) of power providers—or to one another—due to latency constraints, however, HCF extends this range to 90 kilometers (56 miles).</cite> For hyperscalers trying to distribute compute closer to power sources and away from congested urban areas, this flexibility is infrastructure gold.

Who's Building This and When

<cite index="5-3">Relativity Networks is working closely with Prysmian Group to scale up production of hollow-core fiber (HCF) in response to the growing infrastructure demands driven by the AI economy and modern data centers.</cite> The partnership is accelerating: <cite index="3-2">Testing at Dura-Line's flagship test facility in Clinton, Tennessee confirmed the reliable installation of a high-density cable incorporating Relativity Networks' ChronoCore™ hollow core fibers at jetting speeds of up to 350 ft/min—demonstrating the technology's readiness of the solution for real-world deployment and marking a meaningful technical step forward for the development of cutting-edge AI optical infrastructure and data center networks.</cite>

<cite index="4-10">Prysmian is already scaling production of Relativity Network's hollow core fiber, including investments in its Eindhoven facility in the Netherlands, while its Claremont, North Carolina, plant has successfully manufactured the cable with 24 hollow core fibers in a 10mm diameter cable.</cite>

What Problem Does This Actually Solve?

The answer is: the power problem. <cite index="6-8,6-9">40% of data centers could face constraints in power availability by 2027 as AI demand continues to ramp up, according to research from Gartner. And McKinsey estimates that global demand for data center energy capacity could rise by 20% or more a year through 2030, with the additional annual demand exceeding 200 gigawatts—which is enough to power 160 million U.S. homes.</cite>

By allowing data centers to operate farther apart without latency penalties, HCF lets operators build in cheaper, less-congested regions with better access to renewable power and cooling. <cite index="10-17">HCF technology enables cloud-computing hyperscalers to locate data centers closer to power sources and water sources, whether they be conventional electric utilities or green-energy providers.</cite>

High-frequency trading firms are also watching closely—microseconds of latency can literally mean millions in profit differences. <cite index="10-4">Hollow Core Fiber (HCF) is capturing the hearts and minds of the optical industry, particularly to serve data center providers and financial trading companies that require high-speed, low-latency capabilities.</cite>

The Caveat: Cost and Real-World Rollout

Hollow-core fiber isn't a drop-in replacement. Cables are more delicate to handle, require new installation techniques, and cost more upfront than conventional fiber. <cite index="9-12,9-13">These figures reflect testing in laboratory settings, rather than real-world deployments of hollow-core fiber. Note, too, that the performance rate of hollow-core fiber networks can vary depending on the exact design of the cables.</cite>

Expect deployment to start with hyperscalers and trading firms in 2026-2027. Mainstream availability in corporate data centers will likely lag by several years. But the momentum is real: every major fiber manufacturer—Corning, Prysmian, Microsoft, STL—is now in the HCF game.

What You Should Do Right Now

If you're planning data center interconnect infrastructure or upgrades in the next 18-24 months, start conversations with your fiber vendors about HCF options, even if you're not ready to deploy. Understand the cost delta and test it in non-critical paths first. For AI clusters and latency-sensitive workloads, hollow-core becomes a real contender against alternatives like optical circuit switching.

If you're evaluating networking options for your ML infrastructure today, NeonCodex AI can help you map out which technologies actually matter for your compute topology—from fiber choices to co-packaged optics to circuit switching tradeoffs. Start modeling your workload demands against these emerging network options now, before your infrastructure is locked in.

Source: [TechCrunch](https://techcrunch.com/2026/08/19/relativity-networks-raises-22-million-to-bring-a-faster-kind-of-fiber-to-data-centers/)