A Josephson voltage standard using a series array of 100 junctions

Levinsen et al. have suggested that the voltage level of the Josephson-effect voltage standard might be increased by using a series array of highly hysteretic junctions which have rf-induced steps crossing the zero current axis. If the Phase lock condition which yields quantization is stable then biasing the array at zero current insures that the voltage across each junction will be quantized, eliminating the need to individually bias the junctions. Here we describe the design and operation of a 100 junction array fabricated using photolithography. The array produced stable quantized voltages up so 27 mV when operated at 20 GHz.