Simulation and Measurement of Simultaneous Gain and Isolation in Kinetic Inductance Traveling Wave Parametric Amplifiers

ORAL

Abstract

Parametric amplifiers (PAs) permit near-quantum-limited (nQL) noise levels but lack the directionality of semiconducting amplifiers (HEMTs). Without circulators at the PA output, backacting noise from higher temperatures spoils realization of nQL amplification. Commercial ferrite circulators are bulky, lossy, and magnetic – mandating a need for compact and non-magnetic solutions in scaled quantum systems.

Isolation via frequency conversion in PAs is a viable solution. The intrinsic wideband and nonreciprocal nature of traveling wave PAs (TWPAs) enables both nQL amplification and isolation over gigahertz bandwidths. Indeed, Josephson TWPAs have achieved over 30 dB of isolation over nearly 1 GHz [1]. However, JTWPAs are magnetically-sensitive and struggle to achieve dynamic ranges sufficient for high multiplexing factors. Alternatively, kinetic inductance TWPAs (KTWPAs) are resilient to Tesla-scale fields [2] and feature higher dynamic ranges.

We present directional amplification in a KTWPA by measuring isolation of more than 20 dB over bandwidths of 1–2 GHz. Devices are modeled using a multi-mode coupled mode equation solver, twpasolver [3], which supports simultaneous amplification and frequency conversion for forward and backward propagating modes – as well as loss and phase-mismatch-induced gain ripple. Coupled with demonstrations of added noise below 1.5 quanta in circulator-laden amplifier chains [4] directional KTWPAs are promising candidates for demanding readout systems.

*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] A. Ranadive, B. Fazliji, G. L. Gal, G. Cappelli, G. Butseraen, E. Bonet, E. Eyraud, S. B¨ohling, L. Planat, A. Metelmann, et al., A traveling wave parametric amplifier isolator, arXiv:2406.19752 (2024).

[2] L. M. Janssen, F. Faramarzi, H. G. LeDuc, S. Patel, G. Catelani, P. K. Day, Y. Ando, and C. Dickel, Magnetic-Field and Temperature Limits of a Kinetic-Inductance Traveling-Wave Parametric Amplifier, arXiv:2509.15043 (2025)

[3] https://github.com/twpalab/twpasolver

[4] L. Howe, A. Giachero, M. Vissers, P. Campana, J. Wheeler, J. Gao, J. Austermann, J. Hubmayr, A. Nucciotti, and J. Ullom, Kinetic Inductance Traveling Wave Parametric Amplifiers Near the Quantum Limit: Methodology and Characterization, arXiv:2507.07706 (2025).

Presenters

  • Logan Howe

    • California Institute of Technlogy, Pasadena, CA 91125
    • Amazon Center for Quantum Computing

Authors

  • Logan Howe

    • California Institute of Technlogy, Pasadena, CA 91125
    • Amazon Center for Quantum Computing

  • Pietro Campana

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

  • Andrea Giachero

    • University of Milan, Bicocca

  • Michael Vissers

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