PsiQuantum unveils optical device to link GPUs across racks

AI data centers have scaled by networking hundreds of thousands of GPUs, but the copper links between them have become the weak point, especially during training runs that demand heavy coordination. Optical cables are increasingly used, yet they still require converting light to electrical signals and back again billions of times per second, generating heat and bulk through the optical switches involved.

PsiQuantum's device sidesteps those conversions entirely, which Robert Soderbery said would let data flowing between GPUs in separate racks match the speed and latency of GPUs inside one rack. That matters because server racks are approaching limits on compute density, size and energy efficiency, so stretching performance across racks could offer a way around physical constraints.

The company is not alone in pursuing photonics for data center networking. Google already operates a purely optical circuit switching system using MEMS mirrors, while Lightmatter has pushed for standardization and Nvidia has invested billions in optics companies like Lumentum and Coherent. PsiQuantum's entry suggests the race to move data center networking from copper to light is drawing in quantum computing players as well.