Noise performance of a three-wave mixing kinetic inductance traveling-wave parametric amplifier

Kinetic inductance traveling wave parametric amplifiers (KITs) have the potential to read out large numbers of qubits and cryogenic sensors due to their wide bandwidth, high saturation power, and potentially quantum-limited noise performance. However, noise in KITs has so far not been carefully studied, including its dependencies on device design and operating conditions. Here, we present a KIT based on a sub-micron resolution structure that is biased with a dc current and pumped in a three-wave mixing fashion. We experimentally evaluate its noise properties, which approach the quantum limit, and discuss its suitability for readout applications.