Implementation of superconductive passive phase shifters in high-speed integrated RSFQ digital circuits

Abstract

The reduction of the critical current density in rapid single-flux quantum (RSFQ) circuits enables new application fields, like quantum computing and photonic detector readout. The low current density fabrication process creates new design challenges, such as lower stability against thermal fluctuations, violation of the lumped elements condition for microstrip inductances and increased sensitivity to the technological spread. To overcome these issues, we suggest a passive phase shifter as a promising alternative technique for superconductive phase dropping in the RSFQ electronics.