Recently, according to Fierce Network, AWS is deploying hollow core fiber (HCF) to connect 0 data centers. AWS Vice President of Core Network Matt Rehder stated that in the future, hollow core fiber may replace traditional optical fiber and become the standard choice for long- backbone networks.

After about a year of verification, AWS believes that hollow core fiber has met the conditions for large-scale application. Matt Rehder stated that AWS has already HCF to connect about 10 data centers. Although Matt Rehder believes that HCF will play a more important role in the future, there is still a key issue present: insufficient supply.

"The real challenge lies in manufacturability, which is directly related to cost." Matt Rehder said that this kind of optical fiber is extremely to manufacture, especially to produce enough long optical fiber to be actually used for long-distance connection of multiple data centers. The current yield rate is very low, and the manufacturing cost also very high.

Traditional optical fibers are usually made of a solid glass core, while hollow core fibers require multiple hollow glass tubes embedded in a larger glass tube. This itself is quite complex, not to mention achieving large-scale mass production.

Although there have been some recent breakthroughs in manufacturing technology, which has enabled AWS and Microsoft to begin HCF in production environments, market demand for HCF still far exceeds existing supply capabilities.

Supply bottleneck

Although only AWS and Microsoft have publicly announced their HCF deployment plans far, Google and Meta seem to also be closely following this technology. However, there are currently few suppliers of HCF on the market.

Lumenisity, an early company in the HCF field, was acquired by Microsoft in 2022, resulting in a certain vacuum in the market. The main competitors today include Lightera (formerlyS), Chinese manufacturers Changde Fiber Optics and Hengtong Optics. In addition, American startup Relativity Networks has also emerged, and the company reached a agreement with the world-renowned optical fiber manufacturer Prysmian in March 2025 to establish a new HCF production line.

Relativity Networks CEO Jasonichenholz revealed that most of 2025 was spent working with Prysmian to optimize the HCF production process at its factory in the Netherlands. He that in the next few years, the company will increase its annual production from tens of thousands of kilometers to hundreds of thousands of kilometers through Prysmian's global manufacturing network to meet what he describes as "insatiable demand."

"Every kilometer of fiber that I can produce is going to be sold." In the short term Jason Eichenholz expects two to three new companies to enter the HCF space, but he emphasizes, "The feedback that we're getting from the hyperscale customers — if you can't deliver tens of thousands or even hundreds of thousands of kilometers of fiber, you're only going to be a niche player."

He further exempl the demand surge: Relativity Networks received its first purchase order for HCF in 2024, even before the company had hired any employees. "There's onecale cloud provider that basically wants all the products we can make," he says.

Matt Rehder of AWS mentioned that AWS has been working with partners in the HCF to co-design solutions, "trying to help them move forward," and incentivizing suppliers to ramp up investment by making a clear commitment to "buy from you as as manufacturability is solved." Currently, AWS is working with three HCF suppliers.

Testing validation

As for the process of deploying HCF into production environments, Matt Reder said that AWS spent over a year testing HCF and exploring issues such as whether HCF can be compatible with existing optical communication technologies like DWDM and the difficulty of repairing once fiber breaks.

AWS wants to avoid introducing dedicated equipment for HCF to avoid adding extra supply chain and integration complexity. Tests have shown that HCF can indeed be compatible with existing communication equipment, but about 10% to 20% more optical amplifiers need to be deployed along the way than traditional fiber. However, Matt Rehder expects the number of amplifiers needed will gradually decrease as the manufacturing quality of HCF improves.

The development momentum of HCF has attracted the attention of test and measurement company Vi. Recently, Viavi announced the launch of "the industry's first hollow-core fiber long-distance bidirectional test and certification solution." The company said that the solution undergone multiple rounds of verification tests in conjunction with fiber manufacturers, professional engineering service providers, and the top three hyperscale data center operators, and its performance has been fully verified.

 future of hollow-core fiber

Matt Rehder said that AWS is currently only using hollow-core fiber in the metro area, mainly to expand its geographical range in the search land and power resources. This is because HCF can achieve the same delay performance as traditional fiber over longer distances, thus expanding the range of locations where AWS can site its data centers affecting the delay threshold.

Looking to the future, Matt Rehder believes that new fiber optic links may be built entirely with HCF. Even within data centers, H could be used for short-distance connections between servers.

"If you could, you would love to have all your fiber links with hollow-core fiber because it has lower latency and it would be significantly better for certain applications," he concluded. "Of course, it won't be widespread until the cost comes down to a reasonable level. But I it's just a matter of time."