Precision of series-array Josephson voltage standards

Abstract

A 1V seriesarray Josephson voltage standard operated at 35 GHz

Radiation comb generation with extended Josephson junctions

“…This is the power we would measure at a given resonance frequency with a bandwidth exceeding the linewidth of the resonance. To increase the output power, we have considered a linear array of N identical junctions connected together via a superconducting wire as done for the metrological standard for voltage based on the Josephson effect 7,[22][23][24] . The coupling among different junctions has been neglected: This condition can be realized in practice by a suitable design choice which reduces the cross capacitance and the inductance between neighbor junctions.…”

Josephson voltage standards

“…The accuracy of the Josephson voltage-frequency relation Vϭn f /K J , and its independence from experimental conditions, such as bias current, temperature, and junction materials, have been subjected to many tests. 11,[14][15][16][17][18][19][20][21][22] No significant deviation from this relation has ever been found. In the most precise of these experiments, two Josephson de-vices are driven by the same frequency source, biased on the same step, and connected in series opposition across a small inductor.…”

Error Detection Method for RSFQ Voltage Multipliers Using a SQUID Detector

“…Although this method does not measure the absolute value of the output voltage of the VM, the flatness of the constant-voltage region and relative errors in the voltages can be evaluated. Using this method, detection of a voltage difference less than 2 parts in under constant-voltage conditions was demonstrated [7].…”

“…To confirm the correct operation of the VM, a useful method is to carry out the direct comparison proposed for the test of the Josephson frequency relationship [4], [5] and a precise comparison of Josephson voltage standards [6], [7]. Since the output circuit of a VM is a series array of SQUIDs, the difference in the output voltages of two VMs can be measured at very high resolution using superconducting wiring and a SQUID current sensor.…”