High Efficiency Floquet-mode Travelling Wave Parametric Amplifier Characterization and Measurement

Uniform Josephson travelling wave parametric amplifiers (JTWPAs) feature high and broadband gain, but typically feature noise performance 20% below the ideal quantum limit. To suppress sideband noise, Floquet-mode JTWPAs have been proposed and fabricated using the same high-Q fabrication process as superconducting qubits. Here we present efficiency characterizations utilizing both circuit-QED and waveguide-QED calibration methods over a bandwidth of 0.5 GHz. We demonstrate improvement in the intrinsic and full-system efficiencies for a Floquet JTWPA, compared to a uniform JTWPA in the same setup. We then explore the potential of operating the Floquet JTWPA in series with a uniform high-dynamic range JTWPA to further boost full-system efficiency.