Programmable voltage standards based on HTS Josephson junction arrays

摘要

Arrays containing more than 100 shunted bicrystal junctions showed constant voltage steps with applied microwave power at temperatures above 80 K. In contrast to niobium junction arrays with three stable states, only current steps with index n = ±1 were observed in high-T_c circuits. The concept of a programmable voltage standard based on microwave-biased series junction arrays with two stable states is discussed. In this case, in addition to the m segments containing N = 2~m - 1 Josephson junctions, it is necessary to add an extra junction. It serves to set zero voltage on the whole array. Consequently, any output voltage can be selected between 0 and ±2~mΦ_0f in steps of 2Φ_0f.