The prototype of a newly proposed ac-powered Josephson Programmable Logic Array (JPLA) has been fabricated and experimentally investigated. The JPLA can operate more than 10 times as fast as a semiconductor PLA and with one-thousandth of its power dissipation.

A newly developed current injection logic circuit is described. Input signal currents are directly injected into the inductor of a Josephson interferometer instead of being magnetically coupled to it. This circuit realizes excellent isolation characteristics between input and output signals. The additional offset-bias circuit increases the drivability and extends the operating margin. Experimental circuits forming cascade chains of 100 gates were fabricated using 10 µm-square lead-alloy Josephson junctions. The measured switching delay time was about 30 ps at a power dissipation of 15 µW.

The High Tc SQUID was used in an unshielded environment to make eddy current nondestructive testing measurement on a multi-layer aluminum structure. As a demonstration of their capabilities, subsurface defects in a multilayer aluminum structure have been located and mapped using phase shift with no magnetic shielding around the specimen.