Characterization of programmable integrated quantum voltage noise source with variable power spectral density

A quantum voltage noise source (QVNS) based on the Josephson effect as a reference signal is indispensable in precise Johnson noise thermometry (JNT) because it provides quantum accurate power spectral density (PSD) represented by some physical constants and design parameters. An integrated QVNS (IQVNS) device that integrates the circuit elements required for generation of a QVNS signal into one chip has been developed at AIST. The PSD of IQVNS should be variable for precise JNT measurement over a wide temperature range. Here, a new IQVNS device with variable PSD—programmable IQVNS—was developed and the values of the PSD were experimentally confirmed to be consistent with the theoretical values for various design parameters. Thus, JNT measurement over a wide temperature range can be realized with the IQVNS.