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arXiv · 2609.23126

Performance optimization of cascaded traveling wave Josephson parametric amplifiers

Ilari Lilja·Ekaterina Mukhanova·Stanislav Khaldeev·Ilya Golokolenov·Visa Vesterinen·Pertti Hakonen
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Abstract

Traveling-wave parametric amplifiers (TWPAs) based on Josephson metamaterials provide broadband gain with near-quantum-limited added noise. Whereas long nonlinear metamaterial devices can deliver high gain, short arrays suffer less from dissipation, pump depletion, and internal standing waves which can degrade noise performance. Here, we demonstrate a cascaded TWPA architecture that combines the advantages of both approaches by employing a short (736-element), low-dissipation Superconducting Nonlinear Asymmetric Inductive eLement (SNAIL)-based TWPA as the first amplification stage, followed by a conventional long (1632-element) TWPA that provides additional gain. The resulting amplifier cascade achieves nearly 30 dB of total gain over a tunable bandwidth of approximately 1 GHz while maintaining added noise close to the quantum limit. Our results establish a cascade of TWPAs as a practical approach for high-gain, broadband, quantum amplification with applications in quantum information processing, multi-mode entanglement, and quantum sensing applications at microwave frequencies.

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Ilari Lilja, Ekaterina Mukhanova, Stanislav Khaldeev, Ilya Golokolenov, Visa Vesterinen, Pertti Hakonen. 2026-09-19. Performance optimization of cascaded traveling wave Josephson parametric amplifiers. https://arxiv.org/abs/2609.23126

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