A Josephson voltage standard using a superconducting loop containing multiple junctions

This chapter reviews the voltage-current characteristics of a superconducting closed loop and the coherent behavior of the junctions in this loop. In a superconducting closed loop containing several junctions, the phase differences across the junctions depend on each other because of the condition of flux quantization. A 2N-Josephson junction closed loop is examined. The closed loop containing 2N junctions has a high impedance which is N/2 times that of a single junction, and a high output voltage which is N times that of a single junction. The voltage separation of the rf-induced steps corresponds to the frequency separation NF. A computer simulation is performed. It is concluded that by the use of a superconducting closed loop, it is possible to improve the performance of the voltage standard