Performance of an on-chip superconducting circulator for quantum microwave systems

ORAL

Abstract

Microwave circulators enforce a single propagation direction for signals in an electrical network.~ Unfortunately, commercial circulators are bulky, lossy, and cannot be integrated close to superconducting circuits because they require strong (\textasciitilde kOe) magnetic fields produced by permanent magnets.~ Here we report on the performance of an on-chip, active circulator for superconducting microwave circuits, which uses no permanent magnets.~ Non-reciprocity is achieved by actively modulating reactive elements around 100 MHz, giving roughly a factor of 50 in the separation between signal and control frequencies, which facilitates filtering. The circulator's active components are dynamically tunable inductors constructed with arrays of dc-SQUIDs in series. Array inductance is tuned by varying the magnetic flux through the SQUIDs with fields weaker than 1 Oe. Although the instantaneous bandwidth of the device is narrow, the operation frequency is tunable between 4 and 8 GHz. This presentation will describe the device's theory of operation and compare its measured performance to design goals.

*This work is supported by the ARO under contract W911NF-14-1-0079 and the National Science Foundation under grant number 1125844.

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Authors

  • Benjamin Chapman

    • JILA, University of Colorado at Boulder

  • Eric Rosenthal

    • JILA, University of Colorado at Boulder

  • Bradley Moores

    • JILA, University of Colorado at Boulder

  • Joseph Kerckhoff

    • HRL

  • J. A. B. Mates

    • National Institute of Standards and Technology, Boulder

  • Gene Hilton

    • National Institute of Standards and Technology, Boulder
    • National Institute of Standard and Technology - Boulder
    • National Institute of Standards and Technology - Boulder

  • Leila Vale

    • National Institute of Standards and Technology, Boulder
    • National Institute of Standards and Technology - Boulder

  • Joel Ullom

    • National Institute of Standards and Technology, Boulder
    • National Institute of Standards and Technology

  • Kevin Lalumíere

    • University of Sherbrooke

  • Alexandre Blais

    • Institut quantique and D\'epartement de physique, Universit\'e de Sherbrooke, Sherbrooke, Qu\'ebec J1K 2R1
    • University of Sherbrooke

  • Konrad Lehnert

    • JILA, University of Colorado at Boulder, National Institute of Standards and Technology, Boulder
    • JILA and Department of Physics, University of Colorado and NIST
    • JILA and Department of Physics, University of Colorado, Boulder, Colorado 80309, USA