Flux-driven Josephson parametric amplifiers: Hysteretic flux response and nondegenerate gain measurements

Stefan Pogorzalek; Kirill G. Fedorov; Ling Zhong; Jan Goetz; Friedrich Wulschner; Michael Fischer; Peter Eder; Edwar Xie; Kunihiro Inomata; Tsuyoshi Yamamoto; Yasunobu Nakamura; Achim Marx; Frank Deppe; Rudolf Gross

doi:10.1103/physrevapplied.8.024012

arXiv · 1609.09041

Flux-driven Josephson parametric amplifiers: Hysteretic flux response and nondegenerate gain measurements

Stefan Pogorzalek·Kirill G. Fedorov·Ling Zhong·Jan Goetz·Friedrich Wulschner·Michael Fischer·Peter Eder·Edwar Xie·Kunihiro Inomata·Tsuyoshi Yamamoto·Yasunobu Nakamura·Achim Marx·Frank Deppe·Rudolf Gross

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Abstract

Josephson parametric amplifiers (JPA) have become key devices in quantum science and technology with superconducting circuits. In particular, they can be utilized as quantum-limited amplifiers or as a source of squeezed microwave fields. Here, we report on the detailed measurements of five flux-driven JPAs, three of them exhibiting a hysteretic dependence of the resonant frequency versus the applied magnetic flux. We model the measured characteristics by numerical simulations based on the two-dimensional potential landscape of the dc superconducting quantum interference devices (dc-SQUID), which provide the JPA nonlinearity, for a finite screening parameter $\beta_\mathrm{L}\,{>}\,0$ and demonstrate excellent agreement between the numerical results and the experimental data. Furthermore, we study the nondegenerate response of different JPAs and accurately describe the experimental results with our theory.

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Stefan Pogorzalek, Kirill G. Fedorov, Ling Zhong, Jan Goetz, Friedrich Wulschner, Michael Fischer, Peter Eder, Edwar Xie, Kunihiro Inomata, Tsuyoshi Yamamoto, Yasunobu Nakamura, Achim Marx, Frank Deppe, Rudolf Gross. 2016-09-28. Flux-driven Josephson parametric amplifiers: Hysteretic flux response and nondegenerate gain measurements. https://doi.org/10.1103/physrevapplied.8.024012

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