Three Vendors Demo Optical PCIe Prototype to Extend AI Rack Reach

As AI racks become denser and PCIe data rates rise, traditional electrical interconnects face constraints in reach, signal integrity, and cable management. At the 2026 OCP Global Summit, Lumentum (optical components), Astera Labs (smart interconnect chips), and Corning (fiber optics) demonstrated optical PCIe technology, aiming to alleviate these pressures by carrying signals over fiber instead of copper.

The setup combined Astera Labs’ Scorpio Smart Fabric Switch, Lumentum’s optical interconnect, and Corning multimode fiber, using vertical-cavity surface-emitting lasers (VCSELs) to convert PCIe signals into light. Christian Urricariet, senior director at Lumentum, emphasized that this was a proof of concept, not a product announcement.

Joshua Fennimore, commercial technology manager at Corning Optical Communications, noted that passive copper connections are generally limited to a few meters, while optical connections can span tens to hundreds of meters within a data center. This extended reach allows designers to separate GPUs, switches, and memory across different racks, optimizing for compute density, cooling, and serviceability. Jignesh Shah, senior director at Astera Labs, stated that optical PCIe could enable 'scale-up' architectures spanning multiple racks, which current single-enclosure designs cannot support.

Despite the flexibility offered by optical interconnects, copper remains cost-effective for short distances. Shah mentioned that once designs exceed about 3 meters, operators must evaluate both options; currently, copper offers the best total cost of ownership (TCO) within a few meters due to its maturity. Moving from demonstration to broad deployment requires further work on system integration, reliability, manufacturing, and customer qualification.