Fabrication of interface elements for oxide RSFQ circuits

RSFQ circuit elements were fabricated based on the YBa/sub 2/Cu/sub 3/O/sub 7-x/ ramp-edge junctions and their characteristics were investigated. In particular, two types of interface circuits were designed, fabricated and their amplification functions were evaluated. The interface circuits comprised series array of SQUID's that shared a common inductor each other. Each SQUID was switched between zero voltage state and voltage state by current injection. Input signal was AC Josephson current for the type-one interface circuit. The input signal was an SFQ for the type-two interface circuit. Both interface circuits could successfully be operated. In particular, an output voltage more than 1 mV was obtained for the type-one interface circuit that comprised the stack of five SQUID's.