Photonics Coalition Approves Standards to Unlock Optical Scale-Up

Lumentum Holdings told Bloomberg this month that its optical components are "completely sold out" through 2029, and the indium phosphide specialist won't meet demand for some products between now and 2028. Days later, the Advanced Photonics Coalition (APC) has approved a raft of standards it says will enable "high volume manufacturing" of optical networking kit — an attempt to keep shortages and price spikes from strangling the AI buildout.

The announcement landed at the PECC Summit this week, against a backdrop the APC describes in unusually blunt terms. "Without open ecosystem driven standards, the natural gravitational pull is toward vertically integrated proprietary solutions, an outcome that would fragment the market, increase customer lock-in risk, slow adoption, and ultimately diminish the opportunities of innovation for CPO's technical benefits," the coalition wrote in its "Co-Packaged Optics Informative Outlook and Recommended Practices" document released this week.

Why now? Copper is running out of road

AI clusters are hitting what the industry calls the "copper wall." As Gbps demands rise, copper's reach gets shorter while heat and energy consumption climb. Datacenter operators are betting on optics to feed their pricey GPUs more data at lower power.

Earlier this year, Digital Realty CTO Chris Sharp told the BBC: "I think we're at the end of copper," with networking increasingly the factor slowing compute. McKinsey flagged the same problem this month, naming networking an area that "requires improvement" as AI shifts toward inference. It advised operators to "deploy optics-integrated switches (CPO) for higher bandwidth density and lower power per bit," and warned that "a specialized architecture only earns its cost at volume."

Nvidia is paying attention. The company backs Lumentum, and CEO Jensen Huang demonstrated Spectrum X co-packaged optics technology at GTC this week. "So we now have extremely high data rate, extremely high quality data that comes directly onto the chip, and this goes directly into transceivers without going through a PCB and a transceiver goes right into the optics," Huang said.

What does the standards portfolio cover?

Five documents form the released portfolio:

• System Level Architecture Overview for Co-Packaged Optics
• Co-Packaged Optics Informative Outlook and Recommended Practices
• Silicon Photonics for Co-Packaged Optics Recommended Test Practices
• 4-Core Multicore Fiber Cable, Connector and Fiber Array Unit Specification
• Silicon Photonics Manufacturing Specification

"By establishing common manufacturing, interface, and test practices, APC aims to remove implementation variations that add no market value and overcome supply chain silos that constrain volume," the coalition said. The portfolio "supports multiple sourcing and broader supplier participation, helping the industry build an open and scalable photonics ecosystem."

That matters because the supply chain is thin. Lumentum's warnings raise the fear that optical components could follow high-end DRAM and flash into shortage and surging prices. China is a major producer of indium phosphide, adding geopolitical stress to a chain already stretched to its limit.

Can you just need fewer transceivers?

Photonics developer Resolight, a member of the APC working group, sees the standards as an endorsement of its nanosecond optical circuit switching (OCS) approach. "There are two technologies that today are independent and actually co-deployed in scale up," CEO Ofer Shapiro said. "One is traditional slow switching OCS that they're using to reconfigure the network. And the other one is data switches that are working 1,000 times faster."

Resolight's architecture keeps payloads in the light domain, cutting repeated optical-to-electrical-to-optical conversions. That, it says, would boost network energy efficiency and sharply cut the number of optical transceivers needed in multi-rack AI scale-up networks.

"The APC CPO specifications address the data-plane integration needed to make native photon routing a practical alternative to electronic data switching," Shapiro said. His advice on constrained indium phosphide supply is characteristically blunt: "need less of it rather than figure out where do we get more." Or, as he put it: "The easiest to source and the greenest transceiver is the one that you don't need."

On nanosecond-level OCS specifically, the APC said: "The objective is not to standardize a particular fast OCS implementation, but to define the control-plane, optical-interface and behavioral framework that allows fast, transparent OCS to operate as a first-class component of an open AI scale-up fabric."

With Lumentum booked through 2029 and demand outrunning indium phosphide supply, the standards' success in enabling multiple sourcing will help decide whether co-packaged optics scales as an open ecosystem — or fragments into proprietary islands.