• Xanadu and ASML will study lithography processes that could reduce light loss in photonic quantum chips
  • The collaboration focuses on manufacturing research and does not include a production order, measured improvement or commercial system timetable

The fact

Xanadu and ASML announced a collaboration on 9 September to study advanced lithography for photonic quantum chips. Their work will focus on manufacturing processes used to create the small structures that guide light through a photonic processor. One area under examination is line-edge roughness, or small irregularities along the edges of features patterned onto a chip. Xanadu and ASML said better control of these features could help reduce optical loss as light travels through the processor.

Xanadu uses photons, or particles of light, to carry out quantum computations. The company identifies optical loss as one of the technical challenges it needs to address as it works towards larger systems with error correction and fault tolerance. No financial terms were disclosed for the collaboration. The companies also did not announce a manufacturing order, a measured reduction in optical loss or a timetable for delivering a commercial fault-tolerant quantum computer.

The assessment

A photonic quantum chip depends on keeping enough light moving through the processor. Small imperfections introduced during manufacturing can cause some of that light to be lost. Better control over how those structures are patterned could therefore help Xanadu reduce a problem that begins when the chip is made.

A lower-loss result on one chip would only be a first step. The manufacturing process also needs to produce similar results repeatedly. Future testing will need to show whether any improvement can be reproduced across several chips rather than achieved only once.

For BTW readers, the collaboration is a manufacturing research step rather than evidence that a commercial fault-tolerant quantum computer is close. Published optical-loss measurements and consistent results across multiple devices would make it easier to judge what the partnership has actually achieved.

What to watch

Watch for Xanadu and ASML to publish optical-loss measurements from the lithography work and explain how the tests were carried out. Similar results across several chips or fabrication runs would provide stronger evidence that any improvement can be repeated in manufacturing.