Development of a Picosecond Cryo-Sampler Using Electro-Optic Techniques

Abstract

The first all-superconducting sampler, with a rise time of 26 ps, was reported by Faris in 1980 [1]. Recently, an improved version was developed by Wolf et al. with a 2.1 ps response [2]. In this approach, a Faris puiser [1] is used to superimpose a fast current spike on an unknown waveform. This sum signal is then applied to a sense junction, whose dc bias is adjusted to reach the switching threshold. By sweeping the fast pulse in time, the unknown signal can be replicated. The speed of these systems was limited by the response time of the superconducting Josephson junctions, although junctions with switching speeds on the order of one picosecond are possible.