High-gain weakly nonlinear flux-modulated Josephson parametric amplifier using a SQUID-array

TL;DR

This paper presents a high-gain, quantum-limited microwave parametric amplifier using a SQUID array, demonstrating significant improvements in gain, bandwidth, and compression point over single SQUID designs.

Contribution

The authors develop and experimentally validate a flux-modulated Josephson parametric amplifier with an SQUID array, achieving enhanced performance metrics compared to single SQUID configurations.

Findings

Maximum gain of 31 dB at 5 GHz

Bandwidth above 60 MHz at high gain

Compression point of -123 dBm at 20 dB gain

Abstract

We have developed and measured a high-gain quantum-limited microwave parametric amplifier based on a superconducting lumped LC resonator with the inductor L including an array of 8 superconducting quantum interference devices (SQUIDs). This amplifier is parametrically pumped by modulating the flux threading the SQUIDs at twice the resonator frequency. Around 5 GHz, a maximum gain of 31 dB, a product amplitude-gain x bandwidth above 60 MHz, and a 1 dB compression point of -123 dBm at 20 dB gain are obtained in the non-degenerate mode of operation. Phase sensitive amplification-deamplification is also measured in the degenerate mode and yields a maximum gain of 37 dB. The compression point obtained is 18 dB above what would be obtained with a single SQUID of the same inductance, due to the smaller nonlinearity of the SQUID array.