Achieving Sub-100-ns Switching of Programmable Josephson Arrays

Abstract

The accuracy of voltage waveforms, generated using programmable Josephson junction arrays, is limited by the time taken to switch between quantized levels. Relevant parameters are the time constants within the array chip, the characteristics of the cables, and the bandwidth of the bias electronics. A drive system for a 1-V SINIS array with 8192 junctions has been optimized, and a cable scheme has been devised which compensates for cable reflections. The measurements of the array's temporal response, made with this cable system, are compared to an RC model, both with 3- and 7-ns single time constants