Researchers have developed the world's smallest silicon chip quantum photodetector

Researchers at the University of Bristol have made significant breakthroughs in expanding quantum technology by integrating the world's smallest quantum photodetector onto silicon chips. The paper "A Bi CMOS Electron Photon Integrated Circuit Quantum Photodetector" was published in Science Advances.

In the 1960s, scientists and engineers were able to miniaturize transistors onto inexpensive microchips for the first time, marking a crucial moment in the beginning of the information age.

Now, scholars from the University of Bristol have demonstrated for the first time the integration of quantum photodetectors smaller than human hair onto silicon chips, bringing us closer to the era of quantum technology utilizing light.

The large-scale manufacturing of high-performance electronics and photonics is the foundation for achieving the next generation of advanced information technology. Understanding how to manufacture quantum technology in existing commercial facilities is a continuous international effort, and university research and companies around the world are working to address this issue.

Due to the expectation that building a single machine requires a large number of components, it is crucial for quantum computing to be able to manufacture high-performance quantum hardware on a large scale.

To achieve this goal, researchers from the University of Bristol have demonstrated a quantum photodetector that is implemented on a chip with a circuit area of 80 microns x 220 microns.

It is crucial that small size means that quantum photodetectors can be faster, which is the key to unlocking high-speed quantum communication and achieving high-speed operation of optical quantum computers.
The use of mature and commercialized manufacturing technologies helps to integrate other technologies such as sensing and communication as early as possible.

"These types of detectors are called homodyne detectors and can be seen everywhere in the application of quantum optics," explained Professor Jonathan Matthews, director of the Quantum Engineering Technology Laboratory leading the research.

"They operate at room temperature, and you can use them for quantum communication in extremely sensitive sensors such as state-of-the-art gravitational wave detectors, and some quantum computer designs will use these detectors."

In 2021, the Bristol team demonstrated how to connect photon chips with individual electronic chips to improve the speed of quantum photodetectors - now, through a single electron photon integrated chip, the team has further increased speed by 10 times while reducing footprint by 50 times.

Although these detectors are fast and small in size, they are also very sensitive.
"The key to measuring quantum light is sensitivity to quantum noise," explained Dr. Giacomo Ferrarti, the author.
"Quantum mechanics is responsible for the small, fundamental noise levels in all optical systems. The behavior of this noise reveals information about the types of quantum light propagating in the system, determines the sensitivity of optical sensors, and can be used to mathematically reconstruct quantum states. In our research, it is important to demonstrate that making detectors smaller and faster does not hinder their sensitivity in measuring quantum states."

The author points out that there is still more exciting research to be done in integrating other disruptive quantum technology hardware into chip scale. The use of new detectors requires improved efficiency and some work to be done to test the detectors in many different applications.

Professor Matthews added, "We have manufactured detectors using commercial foundries to make their applications easier to implement. While we are very excited about the impact of a range of quantum technologies, it is crucial that we, as a community, continue to address the challenge of scalable manufacturing with quantum technology.".

"If truly scalable quantum hardware manufacturing is not demonstrated, the impact and benefits of quantum technology will be delayed and limited."

Source: Laser Net