, , , , Yonuk Chong
The voltage from a single, microwave-biased Josephson junction is a small quantity; thus useful voltages are only generated through series arrays of many thousands of junctions. Arrays of superconductor-normal metal-superconductor junctions have been fabricated and tested with up to 16,500 junctions per array. The arrays are optimized for the highest voltage operation with the largest operating margins for the current bias. Measurements show that these arrays, driven with 20 GHz microwaves, generate a dc voltage greater than 680 mV per array with over 1 mA dc bias margin. In an effort to increase the microwave uniformity across the array, the transmission line impedance has been tapered. Using this technique, ac Josephson voltages over 110 mVrms per array have been generated, also with over 1mA dc bias margin.
IEEE Transactions on Applied Superconductivity
Josephson Voltage standard, microwave devices, SNS junctions