Progress towards a near quantum-limited Josephson travelling wave parametric amplifier based on Nb-Al/Al₂O₃-Nb trilayer technology.

The interest in travelling wave parametric amplifiers (TWPAs) has dramatically increased over the past decade due to their ability to enhance quantum efficiency of measurements while retaining a large bandwidth and dynamic range essential for the operation of large-scale frequency-multiplexed systems. Here we report on the developments in the fabrication of a TWPA based on Josephson transmission line periodically loaded with resonators for phase-matching. We present the optimized process for the fabrication of the Nb-Al/Al₂O₃-Nb trilayer-based Josephson circuits and the results of the characterization of the fabricated devices.