Ultrafast, electrooptic testing of superconducting electronics

A new era is upon us, one in which electronic device speeds have surpassed that of conventional measurement tools making time-domain characterization of high-speed electronic circuits extremely difficult. However, an optical interface capable of providing subpicosecond input pulses and a non-intrusive measurement technique is well suited to perform these tasks. Electro-optic sampling is one such minimally invasive technique which provides in situ, nodal characterization of electronic devices. Featuring submillivolt sensitivity and subpicosecond temporal resolution, this system is capable of time-domain probing of micrometer-scale electronic devices over a wide temperature range: from 2 K to 300 K. Using this system, ultrafast electronic processes of optoelectronic materials, microwave transmission lines, and an emerging high-speed logic family are experimentally examined.;First, the development of a modern electro-optic sampling system and its application to time-domain, terahertz-bandwidth device measurements are described. With the ability to measure subpicosecond electrical transients, this system is capable of studying electronic processes in a variety of materials from semiconductors to superconductors. Analyses of this type have been performed on many materials, detailing their responses to femtosecond optical pulses. This analysis has lead to the development of newer and faster optoelectronic switches.;After analyzing the performance of optoelectronic switches, the attention is focused on their application in high-speed circuits. Optoelectronic switches are ideally suited to this task since they generate some of the fastest electrical pulses. The propagation characteristics of these pulses is studied on superconducting microstrip waveguides. Attributes such as group velocity, attenuation, dispersion and crosstalk of these waveguides are studied at frequencies exceeding 100 GHz.;With the characterization of these optoelectronic pulses propagating on superconducting waveguides completed, these are implemented as input sources for examining a new high-speed logic family. This logic family is based upon superconducting tunnel junctions which shuttle quantized magnetic flux around in a circuit at speeds exceeding 20 GHz. The experimental observations of these devices are some of the first the time-domain measurements ever performed. The terahertz-bandwidth electro-optic sampling system provides a useful tool for fully characterizing the performance of these devices in the time-domain.