The future of co-packaged optics (CPO) played out in near-real time last week as an almost metaphysical link between the OFC event happening in Los Angeles and Nvidia’s GTC event in San Jose, California, with speakers at both venues coyly hinting at when CPO will become a commercial scale-up connection link.

CPO is expected to soon become a significant connection player for scale-out connectivity, bolstered by its performance benefits. With that assumed, the market is now attempting to discern if and when CPO becomes a choice for scale-up.

Tom O’Malley, equity research director at Barclays Investment Bank, told an OFC panel audience that a recent poll of the firm’s investors showed robust expectations in terms of growing network port need, but the use of CPO in those ports would continue to be muted in the near term.

“Most investors think CPO is less than 15% of Nvidia switches in 2026,” a number that O’Malley said topped out pre-event to at most 30% by 2027. However, O’Malley then added that those expectations are likely to drop coming out of the duo of events.

“Going into this show, the investment community was wild around the timing of CPO, and the expectation was that at the same time that we were all here at GTC, [Nvidia CEO Jensen Huang] would talk a bit more about scale-up architectures as well,” O’Malley said, adding that while Huang did eventually touch on CPO it was probably not enough for CPO supporters. “I would argue that, versus the excitement that we see going to the show, the investment community is probably a little bit more skeptical around the timing of deployments in [2026], in [2027] versus the amount of time that we spend on CPO here at the show.”

O’Malley’s comments were based on Huang’s continued robust support of copper for scale-up networking environments, as expressed during a speech at GTC, a notion further backed by Nvidia networking SVP Gilad Shainer.

“There is nothing better than copper," Shainer told SDxCentral at the GTC event. "Copper is zero power. Copper is passive. There's no active component. … If you can use copper, use copper. And if we can use copper, we want to use copper.”

What color is CPO?

That’s not to say that CPO is being ignored. Many large vendors, including Nvidia, Broadcom, and Cisco, remain high on CPO’s future; it’s just the timing that remains in flux. O’Malley color-coded this flux to “an ecosystem that's involved in many stages between the black of electrical and white of optical.”

“Over that period of time, you're gonna see a lot of gray,” O’Malley said, adding that scale-up will follow scale-out, but the timing remains unknown.

“You obviously see, based on Jensen's comments, kind of a two- to three-year gap,” O’Malley said. “But when does scale up go to optical? 2029. A little later than some of the forecasts have shown.”

Cisco CEO Chuck Robbins recently told investors that the vendor remains confident of the CPO opportunity, whenever it may come.

“We absolutely believe it's going to happen, we all believe it's actually imminent right now,” Robbins said. “If you recall, we actually demonstrated this technology, I think, two years ago or more, and so we have the technology to build it, and we will, as customers want it. But today, they want choice, and I think in many cases, customers want the differentiation between optics and silicon, so they have choice, and they don't get locked in. It reduces their multivendor choice.”

Broadcom CEO Hock Tan proffered a similar argument during that vendor’s most recent earnings call, noting that while CPO is lining up to be a way to “create basically, much better, more efficient, lower power interconnects in not just scale out, but hopefully scale up,” before adding, “I could see a point in time, in the future, when silicon photonics matters as the only way to do it. … We're not quite there yet, but we have the technology, and we continue to develop the technology.”