Dresden 2026 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 28: Superconducting Electronics: SQUIDs and other Josephson Circuits and Components

TT 28.8: Vortrag

Dienstag, 10. März 2026, 11:30–11:45, CHE/0089

Increased added noise in traveling-wave parametric amplifiers due to frequency conversion — •Christoph Kissling, Victor Gaydamachenko, Daniel Valenzuela, Judith Felgner, and Lukas Grünhaupt — Physikalisch-Technische Bundesanstalt, Braunschweig, Germany

Traveling-Wave Parametric Amplifiers (TWPAs) are cornerstone components in quantum microwave technology, offering wide bandwidths and noise performance close to the quantum limit. Added noise above the quantum limit is usually attributed to dielectric loss in the circuit, or to unwanted parametric processes involving higher frequencies. Here we discuss another contribution, originating from spurious waves at frequencies much lower than signal and pump frequencies, unintentionally picked up in the setup and propagating through the TWPA. These waves can drive parametric frequency conversion, transferring energy from the signal, idler, and pump waves to unwanted sidebands. The generation of these sidebands increases the added noise, reduces gain, lowers saturation power, and can produce readout-channel crosstalk through frequency collisions. Particularly severe is the increase of noise: a gain reduction of 2 dB can lead to a noise increase of ca. one photon. Mitigating this effect is crucial for the practical use of TWPAs, allowing operation at the full potential of the devices.