Advanced Modeling and Design Optimization of Josephson Parametric Amplifiers

Josephson parametric amplifiers (JPAs) are essential components for quantum-limited readout in superconducting quantum computing systems, enabling high-fidelity quantum non-demolition measurements through amplification of weak microwave signals. However, their optimal design and characterization remain challenging due to narrow bandwidth, complex nonlinear dynamics, and the interplay between device architecture and performance metrics.

This work presents a comprehensive approach to JPA development, combining advanced modeling techniques with systematic experimental characterization. We address the simulation challenges inherent to flux-driven SQUID-based JPAs, which but present difficulties in modeling flux-pumping dynamics. Building on recent comparative studies of harmonic-balance, pumpistor, and finite-element methods, we developed a modeling approach that leverages harmonic-balance accuracy while incorporating geometric considerations from FEA. This method enables direct simulation of nonlinear Josephson dynamics, offering practical predictive capability for experimental design.

Our experimental characterization investigates key performance metrics including frequency tunability under various bias conditions, maximum achievable gain, added noise, and 1 dB compression point. Through systematic studies, we establish design principles that correlate simulation predictions with measured performance. These findings contribute to the development of high-performance quantum readout systems with improved operational range, measurement sensitivity, and reliability for quantum computation applications.