We demonstrate a Josephson parametric amplifier design with a band-pass impedance matching network based on a third-order Chebyshev prototype. We measured eight amplifiers operating at 4.6 GHz that exhibit gains of 20 dB with less than 1 dB gain ripple and up to 500 MHz bandwidth. The amplifiers further achieve high output saturation powers around -73 dBm based on the use of rf-SQUID arrays as their nonlinear element. We characterize the system readout efficiency and its signal-to-noise ratio near saturation using a Sycamore processor, finding the data consistent with near quantum limited noise performance of the amplifiers. In addition, we measure the amplifiers' intermodulation distortion in two-tone experiments as a function of input power and inter-tone detuning, and observe excess distortion at small detuning with a pronounced dip as a function of signal power, which we interpret in terms of power-dependent dielectric losses.
@article{arxiv.2305.17816,
title = {Josephson parametric amplifier with Chebyshev gain profile and high saturation},
author = {Ryan Kaufman and Theodore White and Mark I. Dykman and Andrea Iorio and George Stirling and Sabrina Hong and Alex Opremcak and Andreas Bengtsson and Lara Faoro and Joseph C. Bardin and Tim Burger and Robert Gasca and Ofer Naaman},
journal= {arXiv preprint arXiv:2305.17816},
year = {2023}
}