PsiQuantum Unveils Silicon Photonic Switch to Accelerate GPU Networks in AI Data Centers
American company adapts quantum computing know-how to create a moving-parts-free optical circuit switch that reduces light loss and promises to relieve GPU traffic congestion
PsiQuantum, an American company known for developing photonic quantum computers, has presented a prototype optical circuit switch (OCS) aimed at GPU networks in artificial intelligence data centers. The device uses circuits etched into a silicon chip with no moving parts — an approach distinct from the micro-mirror-based switches used by competitors such as Google and Lumentum.
The logic of OCS is simple in essence and complex in execution: light passes through the switch directly from fiber to fiber, without conversion to electrical signals and back. Conventional switches perform this conversion at every hop, which consumes energy and adds latency. The optical circuit, in turn, maintains a fixed path of light until a change is ordered.
Why electrical conversion became a bottleneck
The problem PsiQuantum is trying to solve grows in scale as AI clusters expand. Moving data between GPUs is rapidly becoming a bottleneck, and optics represent a leap in bandwidth over copper, which has range limitations. The goal is to improve bandwidth and communication distance so that different GPU racks can talk at high speed and act as a single system.
The main penalty of OCS is the amount of light lost while traversing the switch. In this regard, PsiQuantum's prototype comes in below 2 dB — or less than 37% light loss — a level similar to solutions from Salience Labs and iPronics, which use built-in amplification. Google's mirror-based Palomar switch also typically stays below 2 dB.
The prototype's disadvantage: scale
The weak point of PsiQuantum's device is the number of ports. The prototype has only eight, compared with 136 for Google's Palomar and 300 for Lumentum. Salience Labs operates with 32. The company says it has plans to develop larger devices, but the road to parity with competitors is still long.
PsiQuantum's bet is that the moving-parts-free architecture brings durability and stability advantages in data center environments, where mechanical components suffer wear. The company has not disclosed timelines for a commercial version or capacity targets for the larger devices under development.