Kinetic Inductance Traveling Wave Parametric Amplifiers Near the Quantum Limit: Methodology and Characterization

TL;DR

This paper introduces a new design and simulation framework for kinetic inductance traveling wave parametric amplifiers (KITs) using NbTiN, achieving high gain, broad bandwidth, near-quantum-limited noise, and high dynamic range with simpler fabrication.

Contribution

The paper presents a novel methodology for designing KITs with improved performance metrics and resilience, advancing the state-of-the-art in quantum-limited amplification technology.

Findings

Achieved power gains above 25 dB and bandwidths over 3 GHz.

Demonstrated system noise levels of 1.1 quanta without magnetic shielding.

Showed higher dynamic range and magnetic field resilience compared to Josephson-junction TWPAs.

Abstract

We present a detailed simulation and design framework for realizing traveling wave parametric amplifiers (TWPAs) using the nonlinear kinetic inductance of disordered superconductors -- in our case niobium-titanium-nitride (NbTiN). These kinetic inductance TWPAs (KITs) operate via three-wave mixing (3WM) to achieve high broadband gain and near-quantum-limited (nQL) noise. Representative fabricated devices -- realized using an inverted microstrip (IMS), dispersion-engineered, artificial transmission line -- demonstrate power gains above 25 dB, bandwidths beyond 3 GHz, and achieve ultimate system noise levels of 1.1 quanta even when operated with no magnetic shielding. These performance metrics are competitive with state-of-the-art Josephson-junction-based TWPAs but involve simpler fabrication and able to providing three orders of magnitude higher dynamic range ($IIP_1 = -68$ dBm, $IIP_3 = -55$ dBm), and high magnetic field resilience -- making KITs an attractive technology for highly multiplexed readout of quantum information and superconducting detector systems.