Double-Pumped Kerr Parametric Amplifier Beyond the Gain-Bandwidth Limit

TL;DR

This paper introduces a double-pumped Kerr parametric amplifier that achieves a significant bandwidth increase at high gain levels by using two simultaneous drives, surpassing traditional gain-bandwidth constraints.

Contribution

It presents a novel double-pumped approach enabling broadband amplification beyond the gain-bandwidth limit without approaching instability.

Findings

Sixfold bandwidth increase at 20 dB gain

Surpasses conventional gain-bandwidth scaling up to 25 dB

Operates near the quantum limit

Abstract

Superconducting standing$-$wave parametric amplifiers are crucial for the readout of microwave quantum devices. Despite significant improvements in recent years, the need to operate near an instability point imposes a fundamental constraint: the instantaneous bandwidth decreases with increasing amplifier gain. Here we show that it is possible to obtain parametric amplification without instability by using two simultaneous drives that activate phase-preserving gain and frequency conversion. Realized in a granular aluminum dimer with Kerr nonlinearity, our method demonstrates a sixfold bandwidth increase at 20 dB gain, surpasses the conventional gain$-$bandwidth scaling up to 25 dB, and remains near the quantum limit.