By Nate Wolf

Shares of Corning, the glass and fiber maker, fell Thursday after Broadcom's CEO talked down the near-term potential of optical networking at artificial-intelligence data centers. The technology has been part of Corning's appeal to investors.

Corning announced a collaboration with Broadcom last year on co-packaged optics, or CPO, which connects AI chips using optical fiber instead of copper. CPO, Corning argued, would increase processing capacity and power efficiency in data centers.

Optical networking has gained traction for connecting different AI racks. Within the racks themselves -- a process referred to as "scale-up" -- the shift to fiber from copper may not happen this year or even next year, Broadcom CEO Hock E. Tan said on a conference call Wednesday following the chip maker and software company's fiscal first-quarter earnings report.

"Scaling up in a rack, in a cluster domain, you really want to use direct-attached copper as long as you can," Tan said, adding that copper provides "the lowest latency, lowest power, and lowest cost."

Corning stock dropped 5% in premarket trading Thursday. Shares have climbed 65% this year as of Wednesday's close of trading, with the fiber maker emerging as a winner of the AI boom.

Tan's comments are far from a death knell for Corning's optical networking hopes. The transition to CPO is more a matter of "when" than "if."

"We view [Tan's comments] as generally aligned with our view that CPO adoption is still likely 2--3 years away from seeing a meaningful inflection," said William Blair analyst Sebastian Naji in a research note Thursday.

Ciena also traded lower in premarket trading Thursday even after the optical-networking specialist reported better-than-expected earnings and raised its guidance for the current fiscal year. Last month, the company unveiled a new CPO solution of its own that can work with various chip, optical, and interconnect vendors.

Write to Nate Wolf at nate.wolf@barrons.com

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March 05, 2026 09:20 ET (14:20 GMT)

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