PsiQuantum Unveils Optical Circuit Switch for AI

PsiQuantum, the Californian company trying to build a quantum computer out of light, has unveiled its first product line that is not a quantum computer. On 28 October it showed an optical circuit switch for AI data centres, built on the same low-loss silicon photonics it has spent nearly a decade developing for quantum machines.

The device is a demonstration, not a product on sale. PsiQuantum says it is sharing samples with “select prospective customers” and will announce commercial products “in the coming months”. It gave no price, customer names or shipping date.

What PsiQuantum has built

An optical circuit switch routes light from one fibre to another without first turning it into an electrical signal. Conventional switches convert optical signals to electrical and back at every hop, which PsiQuantum’s product page says adds latency and power. As AI clusters grow, moving data between processors has become one of the limits on how big they can usefully get.

PsiQuantum’s first publicly disclosed switch is an 8×8 device, meaning eight inputs and eight outputs. The company describes it as strictly non-blocking, so every input can reach every output, with no moving parts, mirrors or amplification.

In PsiQuantum’s own lab tests, the switch showed typical results of 1.2 dB insertion loss (the light lost passing through), 40 dB crosstalk (how little signal leaks between paths) and a reconfiguration time of under 3 milliseconds. The company says all three beat its initial targets. The release headline claims loss “as low as 1 dB”, a best case rather than the typical figure. No independent results have been published.

From quantum computer to data-centre part

PsiQuantum’s quantum computers need light to travel through very large numbers of components with almost no loss, so it has pushed its photonics harder than most data-centre uses require. Its product page claims component loss 9 to 100 times lower than industry benchmarks, with chips made at GlobalFoundries, the contract manufacturer recently picked to run two new fabs in Malta, New York.

PsiQuantum also works with barium titanate, a material for faster optical switching, at 300mm wafer scale, and uses a 64×64 barium titanate switch in its quantum systems. It says the demonstration switch and its first products work without that material, which leaves it as a route to faster future devices. Larger switches are in development.

“This opportunity exists because we chose to solve the hardest scaling problems at the beginning of our roadmap to utility-scale quantum computing,” said Victor Peng, PsiQuantum’s chief executive. He said the company would keep working towards “the world’s first useful, fault-tolerant quantum computers”.

Rob Soderbery, an executive vice-president, said the demonstration shows the platform “can deliver exceptional performance for optical circuit switching for AI computing”. In September, PsiQuantum signed definitive documentation with the US Department of Commerce to support research and domestic manufacturing of its components, including high-performance optical switches.

A quantum company finds a nearer-term market

The switch gives PsiQuantum something it has not had: a way to sell its technology before a useful quantum computer exists. Quantum hardware firms face long, expensive roadmaps, and PsiQuantum is one of the companies that have reached the final stage of DARPA’s tests for useful quantum computers. Data-centre optics is a market with customers now, and selling into it could also prove PsiQuantum’s chips can be made in volume.

The market is getting crowded. UK start-up Salience Labs recently raised $125 million to scale its own optical switches for AI data centres, and Lightmatter has shown racks that move data with light. An 8×8 switch is small next to what large clusters need, so the commercial test is whether PsiQuantum can keep its loss figures at the much larger port counts buyers will want, and at a price that competes.

The figures so far come only from PsiQuantum’s labs. Until samples reach customers and results are published, the claims are a promising demonstration rather than proof of a product.

What comes next

PsiQuantum says commercial products will be announced in the coming months. The first details to watch for are port count, price and the names of any customers testing the samples.