Developing Josephson junction array chips for microvolt applications

Josephson junction array chips for microvolt applications have been designed and fabricated. A voltage step as small as 1 mu V has been observed for a single junction in the array when it is driven by 483.59 MHz microwave. By selecting different parts of the array, it can output a voltage from 1 mu V to 256 mu V. The flat region of the voltage steps is over 200 mu A. This kind of array is useful for potential microvolt applications.