More than a decade of research and development was required to practically exploit the quantum behavior of superconducting Josephson junctions for ac applications. Sine waves and arbitrary waveforms had to be synthesized with sufficiently large voltage amplitudes; and measurement techniques with appropriate accuracy had to be developed. Two waveform synthesis methods, pulse-driven and stepwise-approximation, have been implemented in a number of practical systems that are presently being used to calibrate audio-frequency ac voltages and power meters, characterize the stability and linearity of analog components, and as an arbitrary waveform source at the heart of an electronic primary thermometer. Some of the important milestones from these efforts, from my perspective, portray the importance of collaboration as well as the challenges that are typical of technology development. Most importantly, these events have shown how important it is to ensure the accuracy of electrical measurements, even when using quantum-based systems.
100 Years of Superconductivity
Chapman & Hall // CRC Press of the Taylor&Francis Group, Danvers, MA
Quantum-based Voltage Waveform Synthesis, 100 Years of Superconductivity, Chapman & Hall // CRC Press of the Taylor&Francis Group, Danvers, MA, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=906800
(Accessed December 7, 2023)