Josephson compensating junction logic

A Josephson superconducting quantum interference device (SQUID) digital logic family was developed that uses the R/sub nn/ region of a Josephson junction (JJ) to compensate for variations in where R/sub nn/ is the effective resistance of a JJ in the linear I-V region beyond the gap. The basic compensating junction logic (CJL) circuit is two 2-input-OR 1-2-1 interferometer isolators that, when switched, inject current into a 2-input-AND 1-2-1 interferometer. The R/sub nn/ region of several JJs is used in series with a resistor to set the current from the power supply to the 2-input-OR interferometers. The 2-input-AND interferometer is implemented with both current injection and magnetic coupling. The latch circuit uses both current injection and magnetic coupling design techniques to increase the range of I/sub O/, inductance, and resistance variation over which the latch will function correctly. Experimental measurements of CJL circuits are described.<>