On-Chip Superconducting Microwave Circulator from Synthetic Rotation

Electrical circulators enforce the unidirectional flow of microwave signals through junctions in transmission lines, but off-the-shelf components create large magnetic fields that would interfere with nearby superconducting circuits in quantum-computing hardware. The authors design a circulator based on active modulation of its components, a design that uses no large magnets and may be integrated on the same chip as superconducting circuitry. An analogous problem exists in integrated optical networks, for both quantum and classical information applications, and this approach could be adapted to that context as well.