Step width enhancement in a pulse-driven Josephson junction

The response of an overdamped current biased Josephson junction to a pulsed rf drive has been investigated by both numerical and analog simulations. The rf signal was a periodic rectangular pulse of varying amplitude and duration. A considerable increase of the width of the rf-induced steps with respect to those of an equivalent junction driven by a sinusoidal signal has been obtained. In the limiting case of a pulse repetition frequency much lower than the junction RC cutoff frequency, all steps have a maximum width which is independent of the step order n and increases with decreasing pulse duration. (C) 1996 American Institute of Physics.