Challenges of Josephson junction arrays for ac voltage generation by microwave pulse power modulation

Voltage pulses with a determined amplitude and width might be the basis for high-precision ac voltage measurements in the future. The pulse width modulation technique makes possible the generation of arbitrary waveforms. In this paper, arrays of SINIS Josephson junctions were investigated which produce a 1 V voltage step under irradiation at a frequency of the order of 70 GHz. This step has an amplitude of 1 mA whereof a region of 0.3 mA overlaps with the critical current. This allows the generation of a 1 V voltage pulse by switching the microwave power at constant dc bias current. The results of this investigation will be presented and also the array parameters which are required for obtaining a relative uncertainty of 0.1 ppm in ac voltage measurements.