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  • Open Access

Traveling-Wave Parametric Amplifier with Passive Reverse Isolation

C. S. Kow and M. T. Bell*

  • *Contact author: Matthew.Bell@umb.edu
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Phys. Rev. X 16, 021003 – Published 3 April, 2026

DOI: https://doi.org/10.1103/zkyt-r8vd

Abstract

Traveling-wave parametric amplifiers (TWPAs) have attracted much attention for their broadband amplification and near-quantum-limited noise performance. TWPAs are nonreciprocal by nature providing gain for forward-propagating signals and transmission line losses for backward traveling waves. This intrinsic nonreciprocity is insufficient to protect sensitive quantum devices from backaction due to noise from warmer amplification stages in practical systems, and requires the use of bulky cryogenic isolators. We present a multistage TWPA (mTWPA) that addresses this limitation by achieving passive in-band reverse isolation alongside near-quantum-limited noise performance. The multistage architecture consists of two mode conversion stages and a reflectionless high-pass filter that provides the passive isolation. Experimental measurements of a prototype mTWPA demonstrated 20 dB of forward gain across a 1.6 GHz bandwidth and greater than 35 dB of reverse isolation. Noise measurements indicate performance at 1.7 times the quantum limit. This demonstrates that the increased complexity of a multistage TWPA design does not lead to significant added noise. The designed distribution of gain across the stages is engineered to minimize internal amplifier noise at the input, and we propose further optimization strategies in redistribution of the gain between the stages. This level of isolation mitigates noise from warmer amplification stages, matching the performance of conventional isolators. The passive reverse isolation of the mTWPA, allows for the amplifier to operate in pulsed mode where the amplifier is off during qubit gate operations and is turned on during readout allowing for an isolator free scalable readout architecture.

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Popular Summary

Readout of superconducting quantum processors relies on ultra-low-noise microwave amplifiers, but today’s readout chains require bulky isolators that occupy substantial physical space at the coldest stage of a dilution refrigerator, hindering scalability. We present a multistage traveling-wave parametric amplifier that addresses this limitation by distributing gain across multiple stages, enabling tailored impedance matching, frequency conversion, filtering, and passive reverse isolation within a single device. We integrate a reflectionless high-pass filter and exploit signal-to-idler mode conversion to provide passive isolation for backward-propagating waves. We show that this passive reverse isolation remains effective even when the pump is turned off, suppressing back-propagating noise from warmer amplification stages. This capability enables pulsed-mode operation, in which qubit gate operations are performed while the amplifier is off and therefore minimally invasive. We demonstrate 20 dB of forward gain with near-quantum-limited noise performance, establishing a path toward an isolator-free, scalable readout architecture.

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References (60)

  1. J. Aumentado, Superconducting parametric amplifiers: The state of the art in Josephson parametric amplifiers, IEEE Microw. Mag. 21, 45 (2020).
  2. M. Esposito, A. Ranadive, L. Planat, and N. Roch, Perspective on traveling wave microwave parametric amplifiers, Appl. Phys. Lett. 119, 120501 (2021).
  3. A. Fadavi Roudsari, D. Shiri, H. Renberg Nilsson, G. Tancredi, A. Osman, I.-M. Svensson, M. Kudra, M. Rommel, J. Bylander, V. Shumeiko, and P. Delsing, Three-wave mixing traveling-wave parametric amplifier with periodic variation of the circuit parameters, Appl. Phys. Lett. 122, 052601 (2023).
  4. A. Miano and O. A. Mukhanov, Symmetric traveling wave parametric amplifier, IEEE Trans Appl Supercond. 29, 1 (2019).
  5. O. Yaakobi, L. Friedland, C. Macklin, and I. Siddiqi, Parametric amplification in Josephson junction embedded transmission lines, Phys. Rev. B 87, 144301 (2013).
  6. K. O’Brien, C. Macklin, I. Siddiqi, and X. Zhang, Resonant phase matching of Josephson junction traveling wave parametric amplifiers, Phys. Rev. Lett. 113, 157001 (2014).
  7. C. Macklin, K. O’Brien, D. Hover, M. E. Schwartz, V. Bolkhovsky, X. Zhang, W. D. Oliver, and I. Siddiqi, A near–quantum-limited Josephson traveling-wave parametric amplifier, Science 350, 307 (2015).
  8. T. C. White et al., Traveling wave parametric amplifier with Josephson junctions using minimal resonator phase matching, Appl. Phys. Lett. 106, 242601 (2015).
  9. P. Krantz, M. Kjaergaard, F. Yan, T. P. Orlando, S. Gustavsson, and W. D. Oliver, A quantum engineer’s guide to superconducting qubits, Appl. Phys. Rev. 6, 021318 (2019).
  10. L. Ranzani, M. Bal, K. C. Fong, G. Ribeill, X. Wu, J. Long, H.-S. Ku, R. P. Erickson, D. Pappas, and T. A. Ohki, Kinetic inductance traveling-wave amplifiers for multiplexed qubit readout, Appl. Phys. Lett. 113, 242602 (2018).
  11. S. Krinner, S. Storz, P. Kurpiers, P. Magnard, J. Heinsoo, R. Keller, J. Lütolf, C. Eichler, and A. Wallraff, Engineering cryogenic setups for 100-qubit scale superconducting circuit systems, Eur. Phys. J. Quantum Technol. 6, 2 (2019).
  12. J. Heinsoo, C. K. Andersen, A. Remm, S. Krinner, T. Walter, Y. Salathé, S. Gasparinetti, J.-C. Besse, A. Potočnik, A. Wallraff et al., Rapid high-fidelity multiplexed readout of superconducting qubits, Phys. Rev. Appl. 10, 034040 (2018).
  13. K. Ramanathan, N. Klimovich, R. Basu Thakur, B. H. Eom, H. G. Leduc, S. Shu, A. D. Beyer, and P. K. Day, Wideband direct detection constraints on hidden photon dark matter with the qualiphide experiment, Phys. Rev. Lett. 130, 231001 (2023).
  14. C. Bartram et al., Dark matter axion search using a Josephson Traveling wave parametric amplifier, Rev. Sci. Instrum. 94, 044703 (2023).
  15. R. Di Vora et al. (collaboration QUAX Collaboration), Search for galactic axions with a traveling wave parametric amplifier, Phys. Rev. D 108, 062005 (2023).
  16. V. Elhomsy, L. Planat, D. J. Niegemann, B. Cardoso-Paz, A. Badreldin, B. Klemt, V. Thiney, R. Lethiecq, E. Eyraud, M. C. Dartiailh, B. Bertrand, H. Niebojewski, C. Bäuerle, M. Vinet, T. Meunier, N. Roch, and M. Urdampilleta, Broadband parametric amplification for multiplexed SiMOS quantum dot signals, Phys. Rev. Appl. 24, 064062 (2025).
  17. A. L. Grimsmo and A. Blais, Squeezing and quantum state engineering with Josephson travelling wave amplifiers, npj Quantum Inf. 3, 20 (2017).
  18. J. Y. Qiu, A. Grimsmo, K. Peng, B. Kannan, B. Lienhard, Y. Sung, P. Krantz, V. Bolkhovsky, G. Calusine, D. Kim, A. Melville, B. M. Niedzielski, J. Yoder, M. E. Schwartz, T. P. Orlando, I. Siddiqi, S. Gustavsson, K. P. O’Brien, and W. D. Oliver, Broadband squeezed microwaves and amplification with a Josephson travelling-wave parametric amplifier, Nat. Phys. 19, 706 (2023).
  19. M. Esposito, A. Ranadive, L. Planat, S. Leger, D. Fraudet, V. Jouanny, O. Buisson, W. Guichard, C. Naud, J. Aumentado, F. Lecocq, and N. Roch, Observation of two-mode squeezing in a traveling wave parametric amplifier, Phys. Rev. Lett. 128, 153603 (2022).
  20. M. Houde, L. C. G. Govia, and A. A. Clerk, Loss asymmetries in quantum traveling-wave parametric amplifiers, Phys. Rev. Appl. 12, 034054 (2019).
  21. M. R. Perelshtein, K. V. Petrovnin, V. Vesterinen, S. Hamedani Raja, I. Lilja, M. Will, A. Savin, S. Simbierowicz, R. N. Jabdaraghi, J. S. Lehtinen, L. Grönberg, J. Hassel, M. P. Prunnila, J. Govenius, G. S. Paraoanu, and P. Hakonen, Broadband continuous-variable entanglement generation using a Kerr-free Josephson metamaterial, Phys. Rev. Appl. 18, 024063 (2022).
  22. C. Bockstiegel, J. Gao, M. R. Vissers, M. Sandberg, S. Chaudhuri, A. Sanders, L. R. Vale, K. D. Irwin, and D. P. Pappas, Development of a broadband NbTiN traveling wave parametric amplifier for MKID readout, J. Low Temp. Phys. 176, 476 (2014).
  23. N. Zobrist, B. H. Eom, P. Day, B. A. Mazin, S. R. Meeker, B. Bumble, H. G. LeDuc, G. Coiffard, P. Szypryt, N. Fruitwala et al., Wide-band parametric amplifier readout and resolution of optical microwave kinetic inductance detectors, Appl. Phys. Lett. 115 (2019).
  24. D. Pozar, Microwave Engineering (Wiley, New York, 2012).
  25. M. Malnou, M. R. Vissers, J. D. Wheeler, J. Aumentado, J. Hubmayr, J. N. Ullom, and J. Gao, Three-wave mixing kinetic inductance traveling-wave amplifier with near-quantum-limited noise performance, PRX Quantum 2, 010302 (2021).
  26. W. Zhang, W. Huang, M. E. Gershenson, and M. T. Bell, Josephson metamaterial with a widely tunable positive or negative Kerr constant, Phys. Rev. Appl. 8, 051001(R) (2017).
  27. M. T. Bell and A. Samalov, Squid-based traveling wave parametric amplifier US Patent No. US11277107B2 (2022).
  28. M. T. Bell and A. Samolov, Traveling-wave parametric amplifier based on a chain of coupled asymmetric squids, Phys. Rev. Appl. 4, 024014 (2015).
  29. C. Kow, V. Podolskiy, and A. Kamal, Self-phase-matched broadband amplification with a left-handed Josephson transmission line, Phys. Rev. Appl. 24, 024026 (2025).
  30. L. Planat, A. Ranadive, R. Dassonneville, J. Puertas Martínez, S. Léger, C. Naud, O. Buisson, W. Hasch-Guichard, D. M. Basko, and N. Roch, Photonic-crystal Josephson traveling-wave parametric amplifier, Phys. Rev. X 10, 021021 (2020).
  31. B. Ho Eom, P. K. Day, H. G. LeDuc, and J. Zmuidzinas, A wideband, low-noise superconducting amplifier with high dynamic range, Nat. Phys. 8, 623 (2012).
  32. A. Ranadive, M. Esposito, L. Planat, E. Bonet, C. Naud, O. Buisson, W. Guichard, and N. Roch, Kerr reversal in Josephson meta-material and traveling wave parametric amplification, Nat. Commun. 13, 1737 (2022).
  33. R. Boyd and D. Prato, Nonlinear Optics (Elsevier Science, New York, 2008).
  34. G. Agrawal, Nonlinear Fiber Optics, Optics and Photonics (Elsevier Science, New York, 2013).
  35. M. Bell, Josephson traveling-wave parametric amplifier with inverse Kerr phase matching, Phys. Rev. Appl. 25, 014075 (2026).
  36. M. Malnou, B. T. Miller, J. A. Estrada, K. Genter, K. Cicak, J. D. Teufel, J. Aumentado, and F. Lecocq, A travelling-wave parametric amplifier and converter, Nat. Electon. 8, 1082 (2025).
  37. A. Ranadive, B. Fazliji, G. Le Gal, G. Cappelli, G. Butseraen, E. Bonet, E. Eyraud, S. Böhling, L. Planat, A. Metelmann, and N. Roch, A travelling-wave parametric amplifier isolator, Nat. Electon. 8, 1089 (2025).
  38. J. Kerckhoff, K. Lalumière, B. J. Chapman, A. Blais, and K. W. Lehnert, On-chip superconducting microwave circulator from synthetic rotation, Phys. Rev. Appl. 4, 034002 (2015).
  39. B. J. Chapman, E. I. Rosenthal, J. Kerckhoff, B. A. Moores, L. R. Vale, J. A. B. Mates, G. C. Hilton, K. Lalumière, A. Blais, and K. W. Lehnert, Widely tunable on-chip microwave circulator for superconducting quantum circuits, Phys. Rev. X 7, 041043 (2017).
  40. K. M. Sliwa, M. Hatridge, A. Narla, S. Shankar, L. Frunzio, R. J. Schoelkopf, and M. H. Devoret, Reconfigurable Josephson circulator/directional amplifier, Phys. Rev. X 5, 041020 (2015).
  41. F. Lecocq, L. Ranzani, G. A. Peterson, K. Cicak, R. W. Simmonds, J. D. Teufel, and J. Aumentado, Nonreciprocal microwave signal processing with a field-programmable Josephson amplifier, Phys. Rev. Appl. 7, 024028 (2017).
  42. F. Lecocq, L. Ranzani, G. A. Peterson, K. Cicak, X. Y. Jin, R. W. Simmonds, J. D. Teufel, and J. Aumentado, Efficient qubit measurement with a nonreciprocal microwave amplifier, Phys. Rev. Lett. 126, 020502 (2021).
  43. L. Ranzani, S. Kotler, A. J. Sirois, M. P. DeFeo, M. Castellanos-Beltran, K. Cicak, L. R. Vale, and J. Aumentado, Wideband isolation by frequency conversion in a Josephson-junction transmission line, Phys. Rev. Appl. 8, 054035 (2017).
  44. B. Abdo, N. T. Bronn, O. Jinka, S. Olivadese, M. Brink, and J. M. Chow, Multi-path interferometric Josephson directional amplifier for qubit readout, Quantum Sci. Technol. 3, 024003 (2018).
  45. B. Abdo, K. Sliwa, S. Shankar, M. Hatridge, L. Frunzio, R. Schoelkopf, and M. Devoret, Josephson directional amplifier for quantum measurement of superconducting circuits, Phys. Rev. Lett. 112, 167701 (2014).
  46. F. Lecocq, Qubit measurements using nonreciprocal amplifiers, APS March Meeting, MAR-X09 (American Physical Society, Anaheim, CA, 2025).
  47. C. Denney, B. Miller, K. Cicak, K. Genter, J.Teufel, J. Aumentado, and F. Lecocq, Using a traveling-wave parametric amplifier and converter for qubit readout, APS March Meeting, MAR-S09 (American Physical Society, Anaheim, CA, 2025).
  48. Low noise factory products, https://lownoisefactory.com/products/ (2025) (Online; accessed April-2025).
  49. M. T. Bell, I. A. Sadovskyy, L. B. Ioffe, A. Y. Kitaev, and M. E. Gershenson, Quantum superinductor with tunable nonlinearity, Phys. Rev. Lett. 109, 137003 (2012).
  50. M. Tinkham, Introduction to Superconductivity, Dover Books on Physics Series (Dover Publications, New York, 2004).
  51. D. Bothner, D. Wiedmaier, B. Ferdinand, R. Kleiner, and D. Koelle, Improving superconducting resonators in magnetic fields by reduced field focussing and engineered flux screening, Phys. Rev. Appl. 8, 034025 (2017).
  52. T. Dixon, J. W. Dunstan, G. Long, J. M. Williams, P. J. Meeson, and C. D. Shelly, Capturing complex behavior in Josephson traveling-wave parametric amplifiers, Phys. Rev. Appl. 14, 034058 (2020).
  53. A. Y. Levochkina, H. G. Ahmad, P. Mastrovito, I. Chatterjee, G. Serpico, L. Di Palma, R. Ferroiuolo, R. Satariano, P. Darvehi, A. Ranadive, G. Cappelli, G. Le Gal, L. Planat, D. Montemurro, D. Massarotti, F. Tafuri, N. Roch, G. P. Pepe, and M. Esposito, Investigating pump harmonics generation in a snail-based traveling wave parametric amplifier, Supercond. Sci. Technol. 37, 115021 (2024).
  54. S. Whiteley, Josephson junctions in spice3, IEEE Trans. Magn. 27, 2902 (1991).
  55. S. Whiteley, WRspice circuit simulator, http://wrcad.com/wrspice.html (2026) [accessed 3 February, 2026].
  56. A. Y. Levochkina, H. G. Ahmad, P. Mastrovito, I. Chatterjee, D. Massarotti, D. Montemurro, F. Tafuri, G. Pepe, and M. Esposito, Numerical simulations of Josephson traveling wave parametric amplifiers (JTWPAS): Comparative study of open-source tools, IEEE Trans Appl Supercond. 34, 1101306 (2024).
  57. K. Peng, R. Poore, P. Krantz, D. E. Root, and K. P. O’Brien, X-parameter based design and simulation of Josephson traveling-wave parametric amplifiers for quantum computing applications, in 2022 IEEE International Conference on Quantum Computing and Engineering (IEEE, Broomfield, CO, 2022), pp. 331–340.
  58. SEEQC: Digital Quantum Computing—Chip Foundry, https://seeqc.com/ (2026) (Online; accessed 18-January-2026).
  59. H. Renberg Nilsson, D. Shiri, R. Rehammar, A. Fadavi Roudsari, and P. Delsing, Peripheral circuits for ideal performance of a traveling-wave parametric amplifier, Phys. Rev. Appl. 21, 064062 (2024).
  60. M. A. Morgan and T. A. Boyd, Reflectionless filter structures, IEEE Trans Micro Theor. Tech. 63, 1263 (2015).

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Phys. Rev. X 16, 021003– Published 3 April, 2026
  • Received 11 August 2025
  • Accepted 13 February 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.

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