Traveling Wave Parametric Amplifiers (TWPAs) are extensively employed in experiments involving weak microwave signals for their highly desirable quantum-limited and broadband characteristics. However, TWPAs' broadband nature comes with the disadvantage of admitting the activation of spurious nonlinear processes, such as harmonics generation, that can potentially degrade amplification performance. Here we experimentally investigate a Josephson TWPA device with SNAIL (Superconducting Nonlinear Asymmetric Inductive Element)-based unit cells focusing on the amplification behaviour along with the generation of second and third harmonics of the pump. By comparing experimental results with transient numerical simulations, we demonstrate the influence of Josephson junctions' fabrication imperfections on the occurrence of harmonics and on the gain behaviour.
@article{arxiv.2405.20096,
title = {Investigating pump harmonics generation in a SNAIL-based Traveling Wave Parametric Amplifier},
author = {A. Yu. Levochkina and H. G. Ahmad and P. Mastrovito and I. Chatterjee and G. Serpico and L. Di Palma and R. Ferroiuolo and R. Satariano and P. Darvehi and A. Ranadive and G. Cappelli and G. Le Gal and L. Planat and D. Montemurro and D. Massarotti and F. Tafuri and N. Roch and G. P. Pepe and M. Esposito},
journal= {arXiv preprint arXiv:2405.20096},
year = {2024}
}