To process information from quantum circuits and systems, it is important to have amplifiers with wide bandwidth, high dynamic range, and extremely low noise. Parametric amplifiers based on an inductance that varies with electrical current can satisfy these requirements.
We have developed parametric amplifiers based on two different technologies: Josephson Junctions and superconductors with high kinetic inductance, a representation of the kinetic energy of superconducting Cooper-pair charge carriers. Junction-based parametric amplifiers (JPAs) are well suited for measuring the smallest signals of interest such as signals from superconducting qubits. Kinetic inductance-based parametric amplifiers (KITWPAs) are well suited for higher power applications such as measuring the signals from arrays of cryogenic sensors. Both JPAs and KITWPAs can have noise levels near the quantum limit. We have also built frequency combs based on superconductors with high kinetic inductance.