Small device sets new record in super-fast quantum light detection

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

Researchers at Quantum Engineering Technology Labs (QET Labs) at the University of Bristol and the University of Côte d’Azur have designed a new miniaturized light detector to measure the quantum characteristics of light in greater detail than ever before. 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 avenues to surpass the current state of the art in computing, communication, and measurement. Silicon photonics – where light is used as an information carrier in silicon microchips – is an exciting path 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 the LIGO and Virgo gravitational wave observatories to improve their sensitivity, helping to detect exotic astronomical events. such as the black hole So improving the way 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 low quantum characteristics of light. But these detectors have so far been limited in the speed of the signals that can be measured – about a billion 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 bandwidth of your detector, the more calculations you can perform. and convey information quickly, ”said co-lead author Jonathan Frazer.

The integrated detector has so far been clocked 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 footprint of the detector is less than a square millimeter – this small size enables the high speed performance of the detector. The detector is built from silicon microelectronics and a silicon photonic chip.

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

“Much of the focus has been on the quantum part, but now we have started to integrate the interface between quantum photonics and electrical reading. This is necessary for the entire quantum architecture to function efficiently. For homodyne detection, this results in a chip-scale approach in a device with a small footprint for mass production, and most importantly it provides an increase in performance, ”said Professor Jonathan Matthews, who led the project.

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