Josephson Voltage Standard Based on Single-Flux-Quantum Voltage Multipliers

A Josephson single-flux-quantum voltage / frequency multiplier circuit is proposed as the basic building block for a new generation of voltage standards. The circuit uses magnetic coupling to synchronize a series array of independent junction oscillators to the flux flow in a Josephson transmission line. A cascade of these circuits can multiply an arbitrarily low input frequency up to the frequency limit of the circuit (similar or equal to 250 GHz) and then add the voltages across approximately 30000 oscillators to generate precise voltages up to 10 V. Because the oscillators can be switched on and off with a bias current, the output voltage is rapidly programmable. A complete design for a voltage standard programmable in 1.2 mu V increments to a maximum of 10 V is proposed. Using existing fabrication technology, the circuit would cover a substrate area of about 1 cm(2) and use 67 210 junctions.