Ultra High Kinetic Inductance Traveling Wave Parametric Amplifier

ORAL

Abstract

A Kinetic Inductance Traveling-Wave Amplifier (KIT) uses the nonlinear kinetic inductance of superconducting films—particularly Niobium Titanium Nitride (NbTiN)—to achieve high gain, wide bandwidth, and near-quantum-limited noise. Compared to conventional KIT amplifiers fabricated from 20–30 nm NbTiN films with lower kinetic inductance (7–10 pH/sq) three-wave mixing KITs made from 10 nm NbTiN films (~30 pH/sq) demonstrate true gains >25 dB with very low pump power (–45 dBm) and bias current (<1 mA), reducing power dissipation, device backaction due to residual pump leakage,  and footprint (from tens of cm to 8 cm) [1]. Combined with an inverted microstrip design, these compact amplifiers improve fabrication yield and scalability for low-noise quantum readout.

Reducing NbTiN thickness below 10 nm [2] further boosts kinetic inductance, lowering power and size even more. Films as thin as 5 nm (~100 pH/sq) enable the first Ultra-High Kinetic Inductance Traveling-Wave Amplifiers (UHKITs). Their strong nonlinearity allows extremely short devices (~1 cm) and novel slow-light structures with phase velocities ~1/1000 that of light. However, this high inductance regime complicates the microwave line response and amplifier design optimization. Here, we present the design solutions, fabrication process, and characterization results of these first UHKITs and  highlight their performance and potential applications for qubit and detector readout

*This work is supported by the NIST Innovations in Measurement Science program, the National Aeronautics and Space Administration (NASA) under Grant No. NNH18ZDA001N-APRA, the Department of Energy (DOE) Accelerator and Detector Research Program under Grant No. 89243020SSC000058, and DARTWARS, a project funded by the European Union's H2020-MSCA under Grant No. 101027746. Additional support was provided by the Italian National Quantum Science and Technology Institute through the PNRR MUR Project under Grant PE0000023-NQSTI, and by the Italian Research Center on High Performance Computing, Big Data, and Quantum Computing through the PNRR MUR Project under Grant CN00000013-ICSC.

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Publication: [1] L. Howe, A. Giachero et al. arXiv:2507.07706 [quant-ph]
[2] A. Giachero et al. IEEE Trans. Appl. Supercond. 33 (2023) 5, 1700905

Presenters

  • Andrea Giachero

    • University of Milano-Bicocca
    • University of Milan, Bicocca

Authors

  • Andrea Giachero

    • University of Milano-Bicocca
    • University of Milan, Bicocca

  • Logan Howe

    • National Institute of Standards and Technology Boulder

  • Corwin Shiu

    • National Institute of Standards and Technology Boulder
    • National Institute of Standards and Technology (NIST)

  • Michael Vissers

    • National Institute of Standards and Technology Boulder
    • National Institute of Standards and Technology
    • National Institute of Standards and Technology, Boulder

  • Pietro Campana

    • University of Milano-Bicocca
    • University of Milan, Bicocca

  • Jordan D Wheeler

    • National Institute of Standards and Technology Boulder

  • Jason Austermann

    • National Institute of Standards and Technology Boulder
    • National Institute of Standards and Technology
    • NIST

  • Johannes Hubmayr

    • National Institute of Standards and Technology Boulder
    • National Institute of Standards and Technology
    • NIST

  • Joel N Ullom

    • National Institute of Standards and Technology Boulder
    • National Institute of Standards and Technology, Boulder, Colorado 80305, USA