As AI racks pack in more GPUs and PCIe data rates keep climbing, the copper connections that tie those systems together are running into familiar problems: limited reach, signal loss, power draw, heat, and cable clutter. At the 2026 OCP Global Summit in San Jose, three companies showed one possible way around those limits.
Lumentum, Astera Labs, and Corning demonstrated optical PCIe, an approach that keeps the standard PCIe (Peripheral Component Interconnect Express) architecture intact but carries its signals as light over fiber instead of electrical signals over copper. The rack-level demo combined Astera Labs’ Scorpio Smart Fabric Switch, Lumentum’s optical interconnect hardware, and Corning multimode fiber, using VCSEL based optical links. Lumentum was clear that this was a proof of concept rather than a product launch.
Why Copper Runs Out of Room
Distance is the core issue. According to Corning’s Joshua Fennimore, passive copper connections are generally limited to a few meters, with active copper extending somewhat farther, while optical links can span tens to hundreds of meters within a data center. Lumentum’s Christian Urricariet noted that as PCIe data rates rise, electrical links become more sensitive to loss, crosstalk, and equalization needs, often forcing designers to add retimers or keep devices packed closer together, with high-speed copper cables becoming bulky to route.
More Flexible Rack and Row Layouts
The bigger story for operators isn’t fiber replacing copper one for one, it’s what longer reach enables architecturally. Fennimore said fiber’s extended range lets designers separate switches and compute hardware across racks or rows, giving more freedom to optimize layouts around density, power, cooling, serviceability, and cabling.
Astera Labs’ Jignesh Shah said optical PCIe’s tens of meters of reach could support scale-up designs spanning multiple racks, including disaggregated setups with dedicated racks for GPUs, switches, and memory. He added that the approach also supports the high-density links needed for high-radix switches and GPU applications.
Copper Isn’t Disappearing
For short runs, copper remains the practical choice. Shah said that once designs exceed roughly 3 meters, it becomes worth weighing copper against optical, with the decision hinging on power, density, and latency needs. Optical can offer higher density and lower latency, but copper’s maturity still gives it the best total cost of ownership within a few meters.
Early Days
The OCP demo reportedly achieved fully operational optical links using multiple 32 GB/s channels and an error-free PCIe 5 connection in a rack-representative setup. Still, the companies acknowledged that moving from a show-floor demonstration to broad deployment will take more work. For WordPress hosts and data center operators tracking AI infrastructure trends, optical PCIe is worth watching as a potential building block for more modular, composable rack designs down the line, even though it isn’t close to commercial deployment yet.