Dynamic effects in Josephson devices operated as logic gates

The dynamic behavior of Josephson devices, in particular interferometers, is investigated with simple approximations and computer simulations. It is shown that in the latching and in the nonlatching operation modes, the control-inductance plays an important role in the logic delay in circuits with a fan-out of ≥3. The mutual coupling between device and control line results in a crosstalk, which has to be considered in the design by a certain noise margin. For high-performance circuits, Josephson devices with a low ratio of control-line inductance to device inductance are required; besides other advantages, the interferometer meets this requirement better than the in-line Josephson junction.