Investigation Into the Individual Configuration of Superconducting Phase Shift Elements Made of Ferromagnetic Patterns for Reconfigurable Circuits

Reconfigurable superconducting phase shift elements (PSEs) provide high design flexibility in rapid single flux quantum (RSFQ) circuits. Small ferromagnetic patterns were placed on superconducting loops in an RSFQ circuit. The patterns serve as reconfigurable PSEs providing the direction and magnitude of magnetization can be controlled for each pattern individually. A two-dimensional wire mesh architecture was employed to allow for individual configuration and to reduce the number of wires required. Although opposing magnetic fields may occasionally be generated during half-selection using this architecture, experimentally obtained magnetization curves revealed that the orientation of the magnetic field was maintained. An RSFQ circuit, using a reconfigurable PSE, has been successfully demonstrated, potentially leading to large-scale reconfigurable RSFQ circuits

I. Introduction

Energy-Efficient superconducting circuits, such as low-voltage rapid single flux quantum (RSFQ) circuits [1], inductive-biasing RSFQ circuits [2] , energy-efficient RSFQ circuits [3], [4] , reciprocal quantum logic circuits [5], and adiabatic quantum flux parametrons [6] have the potential to further advance the development of supercomputers, with their improved performance as a result of high operating speeds and ultra-low power consumption. A 50-GHz RSFQ microprocessor, implementing functional programs, has been designed and tested [7]. Further advances in superconducting circuit design require increased flexibility without increasing the overall footprint.