A novel microwave isolator has been developed by researchers at the National Astronomical Observatory of Japan (NAOJ), and its fundamental principle, which enables small isolators, has been demonstrated for the first time. This is essential for quantum computers in the future. Two frequency mixers make up this isolator, which paves the way for the creation of large-scale multi-pixel radio cameras as well as receivers for radio telescopes. The paper is distributed in the IEEE Microwave and Remote Innovation Letters.
An electronic part called an isolator is used in quantum computers and radio receivers for astronomy to control the direction in which signals travel.
Because magnetic materials are used in conventional isolators, it is generally challenging to construct isolators smaller than a few centimeters. The development of one million qubit quantum computers on a large scale is hampered by this. There are currently only about 100 qubits in a quantum computer, and increasing this number by 10,000 would necessitate the miniaturization of a large number of components, including isolators. The development of large-format cameras for radio astronomy observations faces the same issue.
“NAOJ has accumulated knowledge in the development of radio wave and visible and infrared light observational instruments. We recently launched the NAOJ ATC’s Social Implementation Program and developed a project team to encourage technological progress for the use of quantum computers. We will continue to make advances in these two areas.”
Yoshinori Uzawa, the NAOJ Director of Engineering.
Instead of magnetic materials, the researchers in this new study used two sets of frequency mixers as isolators and demonstrated the principle experimentally and theoretically.” According to Sho Masui, a Project Researcher at the NAOJ Advanced Technology Center (ATC), “this is based on a completely new principle.” In the microwave band, we have developed a novel circuit device. It is additionally critical, according to an electrical designing perspective, as the new isolator can give profoundly versatile circuits.”
The new isolator’s ability to be completely configured within a flat circuit on a printed circuit board is one of its major scalability advantages. This implies that an isolator with coordinated circuits can be scaled down to the millimeter scale, which is multiple times more modest in volume than regular isolators.
The research team has higher goals. They are looking into developing signal-amplifying isolators. Superconductor-insulator-superconductor mixers (SIS mixers), which are used in a lot of radio observation equipment, are frequency mixers that amplify signals. This new development uses a semiconductor mixer that is already on the market as a frequency mixer. However, if an SIS mixer is used instead, a new device that simultaneously amplifies signals and acts as an isolator will be created.
According to Yoshinori Uzawa, the NAOJ Director of Engineering, “radio wave observation equipment and quantum computers share some common development elements.” NAOJ has developed expertise in the design of radio wave, visible, and infrared light observational instruments. As of late, we laid out the Social Execution Program in the NAOJ ATC and framed an undertaking group to advance mechanical improvement for the utilization of quantum PCs. In these two fields, we will keep making progress.”
More information: Sho Masui et al, A Novel Microwave Nonreciprocal Isolator based on Frequency Mixers, IEEE Microwave and Wireless Technology Letters (2023), DOI: 10.1109/LMWT.2023.3253124
