A Sub-GHz Impedance-Engineered Parametric Amplifier for the Readout of Sensors and Quantum Dots

Mika Prunnila,Visa Vesterinen,Robab Najafi Jabdaraghi,Janne S Lehtinen,Leif Gronberg,Slawomir Simbierowicz,Joonas Govenius

doi:10.1109/tasc.2022.3148965

Abstract

In the work on superconducting parametric amplifiers, the frequency band below one gigahertz is calling for systematic improvements. Despite a prospect for ultralow added noise, bandwidth limitations have slowed down the integration of such amplifiers into sub-GHz experiments demanding fast ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$< 1\, \mu$</tex-math></inline-formula> s) readout speeds. Here, we study the impedance engineering of a flux-driven Josephson parametric amplifier (JPA) at 600 MHz. We propose, simulate and experimentally demonstrate a partially reconfigurable impedance transformer. The transformer enhances the JPA bandwidth to a state-of-the-art value of 10 MHz at 20 dB gain. Our amplifier has immediate applications in the readout of cryogenic sensors and in the reflectometry of quantum dots for spin qubit quantum computing.

Highlights

C RYOGENIC microwave measurements have been benefiting from the development of superconducting amplifiers operating near the quantum limit of added noise
Quite often the corresponding signal frequencies have fallen into the so-called circuit quantum electrodynamics range of about 4–8 GHz: examples include superconducting qubit readout [3] and search for dark matter axions [4]
Kinetic inductance parametric amplifiers are more tolerant than Josephson parametric amplifier (JPA) against stray magnetic fields [17], such as those encountered in quantum dot experiments

Summary

INTRODUCTION

C RYOGENIC microwave measurements have been benefiting from the development of superconducting amplifiers operating near the quantum limit of added noise. Consider a simple scale-down of the operating frequency f of a reflection-type JPA This comes with bandwidth and dynamic range penalties scaling as f and f 2, respectively [10]. Kinetic inductance parametric amplifiers are more tolerant than JPAs against stray magnetic fields [17], such as those encountered in quantum dot experiments. They exhibit a weak non-linearity that puts them at a length and footprint disadvantage in TWPAs [18].

Design

Pumpistor simulation

Fabrication

Characterization

CONCLUSION