Simplified fabrication of magnetically coupled Josephson circuits

We describe a technique for fabricating magnetically coupled Josephson logic and memory circuits and SQUIDs which uses only two superconducting layers. These two layers perform multiple functions as the base and counterelectrodes of the tunnel junctions, the SQUID inductance and control lines, and the signal lines and groundplane between gates. This technique is illustrated by the specific example of a two junction, resistively damped SQUID designed to be fabricated using an all-refractory process which employs a total of five masking levels.