Broadcom continues to push development of its silicon photonics and co-packaged optics (CPO) roadmap, but CEO Hock Tan said that market need is not there just yet.

Tan told investor’s during Broadcom’s recent earnings call that silicon photonics 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.”

“I could see a point in time, in the future, when silicon photonics matters as the only way to do it,” Tan said, before quickly adding, “we're not quite there yet, but we have the technology, and we continue to develop the technology.”

That silicon photonic and CPO development is first being targeted at 400 Gb/s (400G) support, with ongoing development toward 800G and 1.6 Tb/s (1.6T) systems for silicon photonic switches and interconnects. This includes a highly touted test with Meta that that resulted in one million cumulative 400G equivalent port device hours without a single link flap.

Despite that success, Tan remains cautious on the path.

“[I’m] not even sure it will get fully developed because our engineers and our peers we have out there” are looking for “ways to try to do scale up within a rack in copper as long as possible and in scale out in non-pluggable optics,” Tan explained.

Growing market push

Tan’s trepidation aside, Counterpoint Research in a recent report noted that silicon photonics is “the ideal technology” to support co-packaged optics (CPO) and “is central to reshaping data center and networking infrastructure to meet growing bandwidth and energy efficiency needs.” The firm pointed to Nvidia, Intel, Marvell, and Broadcom as being leaders in that space.

The research firm predicts optical platforms – CPO, on-board optics (OBO), and near-package optics (NPO) – will account for around one-third of the market by 2030, and around half of the market by 2033.

That market opportunity has spurred a rash of activity in the space.

Marvell recently announced plans to acquire photonic fabric developer Celestial AI for $3.25 billion. The purchase will see Marvell build out its data center capacity, adding Celestial’s photonic interconnects to its technology portfolio.

Celestial’s Photonic Fabric platform is a full-stack technology capable, which the firm claims can transmit data between data center chips with up to a 25-times increase in off-package bandwidth compared to rival hardware, all while consuming substantially less power.

Patrick Moorhead, CEO and chief analyst at Moor Insights & Strategy, explained that this performance is becoming increasingly important.

“We are hitting the physical limits of copper,” Moorhead wrote in a blog post tied to the Marvell deal. “As we move beyond 1.6T to 3.2T and eventually higher speeds, moving data over copper traces on a PCB or even short-reach cables becomes an issue of physics: power consumption spikes and signal integrity degrades. By acquiring Celestial AI, Marvell is acknowledging that the future of the AI cluster — specifically the memory fabric — is optical. This is not just about plugging a transceiver into the front of a switch. This is about [CPO] and optical interconnects sitting directly next to the compute silicon (XPUs) to disaggregate memory.”

Counterpoint Research’s David Wu noted in that firm’s recent report that “ultimately, we can expect to see an 80x generational leap in performance, with the 3D CPO likely to perform [80-times] better than current solutions.”

Wu’s colleague Leo Liu added that, “what this really means is the delivery of high-speed, high-bandwidth data movement needed for scalable AI clustering, a key step toward democratizing and scaling AI supercomputing capabilities.”

More deals, more money

Marvell’s deal came just a week after GlobalFoundries bought optical chipmaker InfiniLink, which designs optical transceiver chiplets (iOTC) that combine silicon photonics and analog mixed-signal components using advanced packaging. This allows for a more scalable and energy-efficient solution using complete optical engine modules for both pluggable and co-packaged optics (CPO).

Other recent deals in the space include Ciena purchasing optical technology developer Nubis Communications for $270 million, and AMD earlier this year buying silicon photonics startup Enosemi to support the development of photonics and co-packaged optics systems.