Nonlinear Feedback in Josephson Circuit Optimization: Application to a Kerr-Reversal JTWPA
Abstract
Optimizing Josephson-based nonlinear microwave devices is computationally demanding because the straightforward approach requires exploring broad circuit parameter spaces through expensive nonlinear simulations. Josephson Circuits Optimizer addresses this problem by using harmonic balance simulations in two stages: fast linear simulations to select promising circuit configurations according to properties such as impedance and phase matching, followed by nonlinear simulations to optimize their operating conditions. However, pump-induced effects such as impedance renormalization and Kerr-induced modifications of phase matching are not captured during the initial linear stage. We therefore introduce a nonlinear feedback extension that transfers information from the pumped response back to the linear optimization. The approach is investigated using a Josephson traveling-wave parametric amplifier with a reversed-Kerr architecture, whose model is validated against experimental gain measurements. We then evaluate the difference between the linear and pumped response values of a metric based on the input reflection coefficient, while excluding configurations with insufficient third-harmonic suppression. This discrepancy is considered a candidate feedback observable, as it exhibits features similar to the gain landscape, supporting its use in subsequent optimization cycles.
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BibTeX
@misc{palumbo2026nonlinear,
title = {{Nonlinear Feedback in Josephson Circuit Optimization: Application to a Kerr-Reversal JTWPA}},
author = {Emanuele Palumbo and Alessandro Alocco and Andrea Celotto and Luca Fasolo and Bernardo Galvano and Patrizia Livreri and Emanuele Enrico},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.10715},
eprint = {2610.10715},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.10715},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - UNPB
TI - Nonlinear Feedback in Josephson Circuit Optimization: Application to a Kerr-Reversal JTWPA
AU - Emanuele Palumbo
AU - Alessandro Alocco
AU - Andrea Celotto
AU - Luca Fasolo
AU - Bernardo Galvano
AU - Patrizia Livreri
AU - Emanuele Enrico
PY - 2026
DA - 2026/10/07
PB - arXiv
DO - 10.48550/arxiv.2610.10715
UR - https://arxiv.org/abs/2610.10715
AB - Optimizing Josephson-based nonlinear microwave devices is computationally demanding because the straightforward approach requires exploring broad circuit parameter spaces through expensive nonlinear simulations. Josephson Circuits Optimizer addresses this problem by using harmonic balance simulations in two stages: fast linear simulations to select promising circuit configurations according to properties such as impedance and phase matching, followed by nonlinear simulations to optimize their operating conditions. However, pump-induced effects such as impedance renormalization and Kerr-induced modifications of phase matching are not captured during the initial linear stage. We therefore introduce a nonlinear feedback extension that transfers information from the pumped response back to the linear optimization. The approach is investigated using a Josephson traveling-wave parametric amplifier with a reversed-Kerr architecture, whose model is validated against experimental gain measurements. We then evaluate the difference between the linear and pumped response values of a metric based on the input reflection coefficient, while excluding configurations with insufficient third-harmonic suppression. This discrepancy is considered a candidate feedback observable, as it exhibits features similar to the gain landscape, supporting its use in subsequent optimization cycles.
ER -