Pulse driven Josephson voltage standard using modulated optical comb

We have performed an experiment to drive an overdamped superconductor-insulator-normal-insulator-superconductor (SINIS) Josephson junction array (JJA) with modulated current pulse trains, which are generated by modulated ultra short optical pulses. Averaged voltage outputs of the JJA have been systematically measured for various modulation patterns as a function of the bias voltage of an optical modulator. Quantized voltage steps has been clearly observed in accordance with modulation patterns under certain condition of the bias voltage of the optical modulator