Traveling-wave parametric amplifier based on three-wave mixing in a Josephson metamaterial

TL;DR

This paper presents a Josephson traveling-wave parametric amplifier utilizing three-wave mixing in a flux-biased SQUID array, demonstrating broadband, quantum-limited microwave amplification at 4.2 K.

Contribution

The work introduces a practical design for a broadband Josephson parametric amplifier with zero Kerr nonlinearity, enabling efficient phase matching and power gain.

Findings

Successful proof-of-principle experiment at 4.2 K

Demonstrated exponential power gain over a wide frequency range

Validates the concept of a broadband, quantum-limited amplifier

Abstract

We have developed a recently proposed Josephson traveling-wave parametric amplifier with three-wave mixing [A. B. Zorin, Phys. Rev. Applied 6, 034006, 2016]. The amplifier consists of a microwave transmission line formed by a serial array of nonhysteretic one-junction SQUIDs. These SQUIDs are flux-biased in a way that the phase drops across the Josephson junctions are equal to 90 degrees and the persistent currents in the SQUID loops are equal to the Josephson critical current values. Such a one-dimensional metamaterial possesses a maximal quadratic nonlinearity and zero cubic (Kerr) nonlinearity. This property allows phase matching and exponential power gain of traveling microwaves to take place over a wide frequency range. We report the proof-of-principle experiment performed at a temperature of T = 4.2 K on Nb trilayer samples, which has demonstrated that our concept of a practical broadband Josephson parametric amplifier is valid and very promising for achieving quantum-limited operation.