A small footprint travelling-wave parametric amplifier with a high Signal-to-Noise Ratio improvement in a wide band

TL;DR

This paper presents a compact superconducting traveling-wave parametric amplifier with high gain and wide bandwidth, significantly improving signal-to-noise ratio and qubit readout speed for quantum computing applications.

Contribution

The design introduces a small-footprint TWPA using flux-tunable SNAILs with resonant phase matching, achieving high gain and broad bandwidth in a compact form.

Findings

Average gain of 19 dB over 3 GHz bandwidth

Effective SNR improvement of 10 dB

Reduced qubit readout time

Abstract

We characterise a small footprint travelling-wave parametric amplifier (TWPA). The TWPA is built with magnetically flux-tunable superconducting nonlinear asymmetric inductive elements (SNAILs) and parallel-plate capacitors. It implements three-wave mixing (3WM) with resonant phase matching (RPM), a small cutoff frequency for high gain per unitcell and impedance matching networks for large bandwidth impedance matching. The device has 200 unitcells and a physical footprint of only 1.1 mm^2, yet demonstrates an average parametric gain of 19 dB over a 3 GHz bandwidth, an average effective signal-to-noise ratio improvement of 10 dB and a clear speedup of qubit readout time.