Noise Performance of Lumped Element Direct Current Superconducting Quantum Interference Device Amplifiers in the 4 GHz-8 GHz Range

TL;DR

This paper demonstrates a lumped element DC SQUID amplifier operating between 4-8 GHz with noise temperatures below 1 Kelvin, offering significant improvements over existing microwave measurement systems.

Contribution

It provides detailed noise characterization and analysis of a lumped element DC SQUID amplifier, highlighting its low noise performance and potential for enhanced microwave measurements.

Findings

Noise temperature below 1 Kelvin in 4-8 GHz range

Over 10-fold noise reduction compared to existing systems

Characterization of noise behavior as a function of bias parameters

Abstract

We report on the noise of a lumped element Direct Current Superconducting Quantum Interference Device amplifier. We show that the noise temperature in the 4 GHz-8 GHz range over ranges of 10's of MHz is below 1 kelvin (three photons of added noise), characterize the overall behavior of the noise as a function of bias parameters, and discuss potential mechanisms which determine the noise performance in this amplifier. We show that this device can provide more than a factor of 10 improvement in practical system noise over existing phase-preserving microwave measurement systems in this frequency band.