Berlin 2024 – scientific programme

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QI: Fachverband Quanteninformation

QI 26: Superconducting Electronics: Qubits II (joint session TT/QI)

QI 26.1: Talk

Thursday, March 21, 2024, 15:00–15:15, H 2053

Frequency-conversion loss in three-wave-mixing traveling-wave parametric amplifiers — •Christoph Kissling, Victor Gaydamachenko, Marat Khabipov, Alexander B. Zorin, and Lukas Grünhaupt — Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany

Traveling-Wave Parametric Amplifiers (TWPAs) enable near-quantum-limited amplification of weak microwave signals with several GHz bandwidths and saturation powers above -100 dBm. One aspect of current research is the reduction of microwave loss in TWPAs, which is seen as one reason why the added noise of TWPAs stays repeatedly above the quantum limit. Typically, most of the microwave loss is attributed to lossy dielectric layers. However, in this talk we address another loss mechanism which can occur in three-wave-mixing TWPAs. We discuss how frequency-conversion of a probe tone by the presence of noise in the kHz to MHz range can dominate the insertion loss. This potentially-overlooked nonlinear loss mechanism appears like linear loss and can therefore lead to false conclusions in the characterization and optimization of TWPAs.

Keywords: Parametric Amplifiers; Microwave Engineering; Quantum Computing; Qubit Readout; Superconducting Electronics