The tiny device enables a new record in super fast quantum light detection

Bristol researchers have developed a tiny device that paves the way for higher-performance quantum computers and quantum communications, making them significantly faster than the current state of the art.

Researchers from the Quantum Engineering Technology Labs (QET Labs) of the University of Bristol and the Université Côte d’Azur have built a new miniaturized light detector to measure the quantum characteristics of light in more detail than ever. The device, made up of two silicon chips working together, was used to measure the unique properties of “compressed” quantum light at record speeds.

Harnessing the unique properties of quantum physics promises new pathways to surpass the current state of the art in computation, communication and measurement. Silicon photonics, where light is used as an information carrier in silicon microchips, is an exciting road to these next generation technologies.

“Compressed light is a very useful quantum effect. It can be used in quantum communications and quantum computers, and has already been used by gravitational wave observers LIGO and Virgo to improve their sensitivity, helping to detect exotic astronomical events such as the black hole. So improving the ways we can measure it can have a big impact, ”said Joel Tasker, co-lead author.

Measuring compressed light requires detectors designed for ultra-low electronic noise in order to detect the faint quantum characteristics of light. But such detectors have so far been limited in the speed of the signals that can be measured: about a thousand million cycles per second.

“This has a direct impact on the processing speed of emerging information technologies such as optical computers and communications with very low light levels. The higher the detector bandwidth, the faster it is possible to perform calculations and transmit information,” he said. co-lead author Jonathan Frazer.

The integrated detector has so far been synchronized at an order of magnitude faster than the previous state of the art, and the team is working to refine the technology to go even faster.

The detector footprint is less than one square millimeter – this small size allows for high-speed detector performance. The detector is built with silicon microelectronics and a silicon photonic chip.

Around the world, researchers have explored how to integrate quantum photonics on a chip to demonstrate scalable manufacturing.

“Much of the attention has focused on the quantum part, but we have now begun to integrate the interface between quantum photonics and electrical reading. This is necessary for the whole quantum architecture to work efficiently. For homodyne detection, the The chip-scale approach results in a device with a minimal footprint for mass production and, more importantly, provides a performance boost, ”said Professor Jonathan Matthews, who led the project.

“Silicon photonics interfaced with integrated electronics for compressed light measurement at 9 GHz” by Joel Tasker, Jonathan Frazer, Giacomo Ferranti, Euan Allen, Léandre Brunel, Sébastien Tanzilli, Virginia D’Auria and Jonathan Matthews has been published today on Photonics of nature.