Cryogenic Microwave Measurements on Superconducting Circuits at PTB

Accurate microwave measurements at cryogenic temperatures pose many challenges. For such measurements on superconducting circuits, PTB currently develops and pursues two strategies. First, electromechanical switches are used to perform a calibration of the cold cryogenic setup for scattering parameter measurements with conventional vector network analyzers. Second, we employ optoelectronic techniques for in-situ detection of time-domain waveforms. These approaches are, in particular, useful for the characterization of peripherical devices of superconducting qubits such as parametric amplifiers and Josephson pulse generators.