- Corning wants to replace the copper cables in data center servers to optical fiber
- Data centers use a ton of copper for various purposes, which is poised to push their power constraints to the limit
- Corning said co-packaged optics could help address copper constraints in the data center
We’ve heard ad nauseam about the need for fiber connectivity between data centers to support hyperscaler AI growth. But there is still plenty of copper wiring lurking within data centers, presenting a ripe opportunity for optical vendors like Corning.
The advent of AI has driven an increase in the number of graphical processing units (GPUs) in data center server racks, which in turns means more fiber is required to connect these GPUs to one another, Mike O’Day, SVP and General Manager of Corning’s Optical Communications unit, said at the company’s investor event Tuesday.
O'Day made similar comments to Fierce in 2023, but the problem has become more acute thanks to the rise of generative AI and Agentic AI.
“2025 becomes the year of 72 GPU AI nodes like [Nvidia’s] Blackwell,” he said. "These nodes increase the fiber in the switch rack by another factor of four, highlighting a massive opportunity for Corning."
The golden goose lies in the back end of the node, which contains bundles of copper cables. There are typically “2 miles of copper cable in each one of these racks.” He explained in a typical 72 GPU node with six server racks, fiber is connected from the switch rack to each of those server racks, but “that’s where the optical signal ends today.”
Corning wants to replace that cabling with optical fiber technology. And the revenue it could reap by doing so is huge: Dell'Oro Group has forecast that AI back-end networks will grow at a more than 50% CAGR to reach $20 billion by 2028.
But such a swap could be a tall order, because while fiber is a more efficient form of connectivity, copper is used in many areas across the data center today.
Not only is there copper in the wiring and power connectors in the servers themselves, as mining company BHP noted, but it’s also located in places like cooling systems and the external cabling that provides power to the data center.
Bloomberg predicted that by 2030, copper usage in data centers across North America could increase by 1.1-2.4 million tons. “As AI demands mount, so too will server-rack power density and cooling needs, potentially pushing up copper intensity too,” said Bloomberg.
But Claudio Mazzali, Corning’s VP of Global Research, believes the transition from short copper interconnects to fiber in the data center back-end network is “inevitable.”
We’ve already witnessed applications such as submarine, long-haul, metro and access transition from electrical to optical, he said, to “compensate signal loss in copper links.” Now, with hyperscalers doubling down on building more capacity for AI, we’re seeing architectures that are “creating new requirements where electrical transmission of copper will be challenged.”
As you may well know, electricity – not fiber – is probably the biggest constraint for data center growth amid increasing chip power levels, rack densities, among other issues.
The technical nitty-gritty
With data rates poised to continue growing, so will the number of GPUs per node, Mazzali noted. “Consider a single node with hundreds of GPUs distributed over more than 10 racks. Once that happens, the interconnection between GPUs on the same node will need to be extended to more than 30 meters,” he explained.
At that point, “it becomes more cost-effective and energy efficient to transition to optical,” said Mazzali.
He showed an image of Meta’s current server rack architecture, saying “it’s important to note that the signal turns to optical only at the network switch in the purple box in the middle.”
While Mazzali couldn’t disclose exactly how Corning is working with its partners on the future of AI nodes, he did note co-packaged optics are poised to play a key role in addressing the constraints of copper in the data center.
Though co-packaged optics tech has been around for a while, it’s garnered more attention as advanced chips generate 100 Tbps of aggregated input/output, Mazzali explained.
“We started to have hundreds of planes at more than 100 gigabits per second each. Carrying those signals over a distance of just a few centimeters of copper requires advanced digital signal processing or a stronger forward error correction,” he said.
IBM has actually come up with new co-packaged optics tech that tackles this very issue, which could speed up chip-to-chip communication by allowing them to talk to each other via fiber optics instead of electrical technology.
GenAI outlook
All told, Corning is feeling pretty good about the value GenAI is bringing to its enterprise business. The vendor in 2024 reeled in “a record $2 billion” in enterprise revenues, said Corning CEO Wendell Weeks, and “customer adoption continues to track ahead of our expectations.”
Notably, Corning is helping Lumen meet demand for long-haul fiber transport due to AI advances. The companies last August inked a deal through which Lumen would reserve 10% of Corning’s global fiber capacity for the next two years.
“Our production is tripling every month this quarter, so this innovation is now turning into a revenue stream to make a positive difference in our financials this year,” Weeks concluded.