Two-idler parametric amplification with Josephson junctions

Abstract

A self‐pumped Josephson junction can be operated in a mode which is described in first order by a two‐idler parametric amplifier analysis for a sinusoidal elastance variation. Thus the analysis and operation follows the two‐idler negative resistance behavior predicted by Penfield and Rafuse for varactor diodes. Experimental observations on parametric negative conductance excitations at 9 GHz by a Josephson point contact are readily explained by the two‐idler model. A total signal power gain of 12 dB was achieved with an experimental device consisting of a niobium titanium point contact in a shallow rectangular cavity coupled through a room‐temperature circulator.