QuantumCore has begun development of chip-scale magnetless circulators in collaboration with Professor Raafat Mansour of the University of Waterloo’s Department of Electrical and Computer Engineering. These devices aim to solve a growing problem for superconducting quantum computers, which rely on circulators to direct extremely weak microwave signals and isolate qubits from noise.
Conventional cryogenic circulators use bulky ferrite materials and permanent magnets, creating integration challenges as processors scale; QuantumCore proposes a compact, nonmagnetic alternative. “Today’s quantum computers rely on circulators that are measured in centimetres, while the semiconductor industry routinely manufactures complex circuits measured in millimetres,” said Eugene Profis, Chief Executive Officer of QuantumCore.
QuantumCore Develops Chip-Scale Circulators for Quantum Computer Scaling
QuantumCore is using existing work with cryogenic Phase-Change Material (“PCM”)/Superconducting multiplexing microchips to address a new challenge in quantum computing infrastructure. This program aims to shrink a critical component while simultaneously easing integration difficulties as qubit counts climb.
The potential impact extends beyond mere miniaturization, as a chip-scale replacement could consolidate multiple functions, reducing the need for mounting hardware and connectors within the readout assembly. The company anticipates that the benefits of this technology will become increasingly significant as quantum computers scale toward one million qubits, where the physical space occupied by microwave components presents a major engineering hurdle.
QuantumCore intends to integrate these new circulators with its multiplexing technology, enabling the construction of larger quantum computers without a proportional increase in cryogenic infrastructure complexity, the company says. “Our strategy is to build the critical hardware infrastructure that allows quantum computer manufacturers to scale,” added Profis, framing the development as a key element in overcoming infrastructure limitations for quantum computing systems. The research will focus on creating compact, nonmagnetic chips for signal routing and isolation, addressing a core need for signal integrity in superconducting quantum processors.
Today’s quantum computers rely on circulators that are measured in centimetres, while the semiconductor industry routinely manufactures complex circuits measured in millimetres.
Eugene Profis, Chief Executive Officer of QuantumCore
Spatiotemporal Modulation Enables Magnetless Circulator Design
QuantumCore is investigating directional microwave transmission through precisely timed electrical signals, a technique called spatiotemporal modulation, to bypass the need for ferrite materials and permanent magnets in cryogenic circulators. This approach aims to create a pathway for signals to travel in one direction without magnetic bias, potentially enabling compact circulators suitable for superconducting quantum computing. The company’s existing development program involving Phase-Change Material (PCM) and superconducting switching technologies provides a foundation for this new work, with low-loss, broadband switches important components, according to QuantumCore.
The development program is part of a Sponsored Research Agreement with the University of Waterloo, focused on cryogenic multiplexing and magnetless circulators for quantum computer applications. He holds 41 Canadian and U.S. patents and has authored over 475 peer-reviewed technical publications, expertise the company expects will support scalable magnetless circulator development.
Addressing the limitations of current cryogenic infrastructure is a central goal, according to QuantumCore. “Our objective is to move this critical functionality onto compact, nonmagnetic chips that can be integrated with our multiplexing technology, helping the industry build much larger quantum computers without proportionally increasing the size and complexity of the cryogenic infrastructure,” said a company representative. “We believe these technologies can ultimately work together as part of a highly integrated cryogenic infrastructure platform,” the representative added.
Our strategy is to build the critical hardware infrastructure that allows quantum computer manufacturers to scale.
Eugene Profis, Chief Executive Officer of QuantumCore
PCM/Superconducting Integration Reduces Cryostat Complexity
Eliminating magnetic assemblies is central to QuantumCore’s approach to scaling quantum processors, as conventional cryogenic circulators present increasing integration challenges with larger systems. These traditional components, relying on ferrite materials and permanent magnets for nonreciprocal signal transmission, are discrete microwave elements requiring physical installation and thermal anchoring within the cryostat. As superconducting systems aim for thousands of readout channels, the combined volume of circulators, connectors, and cabling could hinder further development.
Mansour’s prior work focuses on advanced switching technologies and cryogenic RF devices, including a history as a Tier 1 Canada Research Chair in Micro-Nano Integrated RF Systems. Key development priorities extend beyond simply removing magnets; QuantumCore is focused on achieving specific performance characteristics, including minimizing insertion loss and power consumption, maximizing isolation and operating bandwidth, and ensuring compatibility with superconducting circuits, all while maintaining scalable fabrication processes, the firm reports.
“We are developing superconducting amplifiers to address heat and signal amplification, PCM/Superconducting multiplexing to address wiring complexity, and now magnetless circulators to address the size and integration limitations of conventional microwave components,” said a company representative.
As superconducting quantum computers scale toward one million qubits, the physical space occupied by thousands of discrete microwave components becomes a major engineering challenge.
Professor Mansour Leads RF and Cryogenic Expertise
The new technology will be developed under QuantumCore’s Sponsored Research Agreement with the University of Waterloo, led by Professor Raafat Mansour of the Department of Electrical and Computer Engineering. This builds on QuantumCore’s existing cryogenic development program, indicating a focused, incremental approach to building essential quantum infrastructure. “His expertise in advanced RF systems, integrated circuit design, cryogenic superconducting technologies and technology commercialization is expected to support QuantumCore’s development of scalable magnetless circulators,” the company stated.
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