Broadband CPW-based impedance-transformed Josephson parametric amplifier

TL;DR

This paper introduces a broadband Josephson parametric amplifier with simplified design, broad bandwidth, low noise, and tunability, suitable for quantum measurement and information applications.

Contribution

The authors develop a broadband IMPA with a horn-like CPW that reduces complexity while maintaining high performance and tunability.

Findings

700 MHz bandwidth at 15 dB gain

Near quantum-limited noise performance

Tunable over 1.4 GHz with flux bias

Abstract

Quantum-limited Josephson parametric amplifiers play a pivotal role in advancing the field of circuit quantum electrodynamics by enabling the fast and high-fidelity measurement of weak microwave signals. Therefore, it is necessary to develop robust parametric amplifiers with low noise, broad bandwidth, and reduced design complexity for microwave detection. However, current broadband parametric amplifiers either have degraded noise performance or rely on complex designs. Here, we present a device based on the broadband impedance-transformed Josephson parametric amplifier (IMPA) that integrates a horn-like coplanar waveguide (CPW) transmission line, which significantly decreases the design and fabrication complexity, while keeping comparable performance. The device shows an instantaneous bandwidth of 700(200) MHz for 15(20) dB gain with an average saturation power of -110 dBm and near quantum-limited added noise. The operating frequency can be tuned over 1.4 GHz using an external flux bias. We further demonstrate the negligible back-action from our device on a transmon qubit. The amplification performance and simplicity of our device promise its wide adaptation in quantum metrology, quantum communication, and quantum information processing.