The University of Bristol’s researchers have made a significant step forward in scaling quantum technology by integrating the world’s smallest quantum light detector onto a silicon chip. In the 1960s, scientists and engineers were able to miniaturize transistors into low-cost microchips, which was a vital step toward unlocking the information age.
For the first time, experts at the University of Bristol have shown the integration of a quantum light detector (smaller than a human hair) onto a silicon chip, bringing us one step closer to the age of quantum technology based on light.
Making high-performance electronics and photonics at scale is critical to realizing the next wave of advanced information technology. Figuring out how to create quantum technologies in current commercial facilities is an ongoing international effort being pursued by university researchers and firms all over the world. Because of the large number of components required to produce even a single machine, the ability to manufacture high performance quantum hardware at scale may be critical for quantum computing.
In pursuit of this goal, researchers at the University of Bristol demonstrated a quantum light detector constructed on a device with a circuit of 80 micrometers by 220 micrometers. Critically, the small size allows the quantum light detector to be quick, which is essential for unlocking high-speed quantum communications and enabling high-speed operation of optical quantum computers.
The adoption of well-established and widely available fabrication techniques improves the potential for early integration with other technologies such as sensing and communications.
These types of detectors are called homodyne detectors, and they appear everywhere in applications across quantum optics,” says Professor Jonathan Matthews, who conducted the study and is Director of the Quantum Engineering Technology Labs. “They operate at room temperature, and you can use them for quantum communications, in incredibly sensitive sensors — like state-of-the-art gravitational wave detectors — and there are designs of quantum computers that would use these detectors.”
In 2021, the Bristol team demonstrated how combining a photonics chip with a separate electronics chip can boost the speed of quantum light detectors; now, using a single electronic-photonic integrated device, the team has increased speed by a factor of ten while reducing footprint by a factor of fifty.
These detectors are fast and tiny, but also sensitive.” The key to measuring quantum light is sensitivity to quantum noise,” writes author Dr. Giacomo Ferranti. “Quantum mechanics is responsible for the fundamental level of noise in all optical systems. The behavior of this noise gives information about what kind of quantum light is moving in the system, it can influence the sensitivity of an optical sensor, and it can be utilized to mathematically reconstruct quantum states. In our study it was important to show that making the detector smaller and faster did not block its sensitivity for measuring quantum states.”
Reference – World’s smallest quantum light detector on a silicon chip
