Fabrication of low-loss Josephson junction based parametric circuits*

Interest in quantum-limited amplification based on Josephson junction based superconducting circuits has increased drastically due to the rapidly advancing field of quantum information processing. To this end, a key challenge is the realization of low-loss superconducting devices. We achieve this goal by employing careful cleaning steps during the fabrication of the superconducting circuits. Upon optimization, we fabricate Josephson parametric devices with internal quality factors in excess of 10^5­. We characterize bandwidth, gain, noise, dynamic range, and other properties of the realized devices. Based on these investigations, we derive useful criteria for the development of more intricate devices incorporating Josephson parametric circuits.