RSFQ electronics for controlling superconducting polarity switches

Abstract

Superconducting radiation sensors are of particular interest for imaging applications in the sub-mm wavelength band because of their extraordinary sensitivity. The rising number of sensors integrated in one array entails the requirement of multiplexing techniques in order to reduce the number of wires leading into the cryogenic stage and thus reduce the thermal losses. One kind of promising code division multiplexing technique is based on a current steering switch (CSS), which is composed of two identical superconducting quantum interference devices (SQUIDs) in parallel current paths. One of them is switched from the superconducting into the normal state controlled by the applied magnetic flux. In this way the signal path can be altered and they can act as a polarity switch for analogue signals. We pursue this concept to use rapid single flux quantum (RSFQ) electronics for controlling these switches. As a first step, the SQUIDs of the CSS are inductively coupled to the storing loops of two delay flip flops (DFFs). Thus, one is able to toggle the polarity of the analogue switch by controlling the state of the DFF by RSFQ control signals. The results of simulations and measurements and also margin analyses are discussed.

Multistability and self-organization in disordered SQUID metamaterials

“…Recent advances that led to nano-SQUIDs make possible the fabrication of SQUID metamaterials at the nanoscale [28]. The use of SQUID arrays in dc current sensors [29], filters [30,31], magnetometers [32], amplifiers [33][34][35], radiation detectors [36], flux-to-voltage converters [37], compact antennas [38,39], linear rf low noise amplifiers [40,41], output amplifiers for rapid single flux quantum (RSFQ) circuits [42,43], drivers for digital transmitters [44], as well as in RSFQ electronics [45], has been suggested and realized in the past. However, in most of these works the SQUIDs in the arrays were actually directly coupled through conducting paths.…”

Design and Evaluation of Magnetic Field Tolerant Single Flux Quantum Circuits for Superconductive Sensing Systems

“…Superconducting sensing systems composed of a superconducting sensor array and single-flux quantum (SFQ) readout circuits [1] have been proposed and implemented to build large-scale multi-channel superconductive sensor arrays [2]- [5]. By using the SFQ read-out circuit, the number of wires that connect the superconducting sensor array and room-temperature instruments can be reduced.…”