Distributed-Coupling Resonant Phase Matching in NbTiN Kinetic Traveling-Wave Parametric Amplifier
by
C101
Changjo-gwan, KAIST (Munji Campus)
Quantum-limited microwave amplifiers are essential for the readout of weak signals in a wide range of experiments, including quantum computing, astronomy, and high-energy experiments such as dark matter axion searches. As these fields continue to grow, there is an increasing need for amplifiers that can provide low noise, wide bandwidth with reduced complexity. In recent studies of superconducting circuits, several approaches have been explored to meet these requirements. Traveling-wave parametric amplifiers have recently emerged as promising candidates for scalable multiplexed readout because they can overcome the bandwidth and dynamic-range limitations of existing resonator-based quantum-limited amplifiers. In particular, Kinetic Traveling-Wave Parametric Amplifiers (KTWPAs) are especially attractive due to their simple fabrication, high power handling, and broadband quantum-limited noise operation. A key challenge in these devices is the realization of efficient and robust phase matching. Recent approaches have employed resonant elements periodically in every few unit cells, achieving broadband high- gain performance through its unique dispersion relation. However, these designs also present fabrication challenges in the implementation of homogeneous lumped resonators. To address these challenges and achieve more efficient phase matching, we previously proposed a distributed-coupling resonant phase-matching (dcRPM) scheme, in which a single waveguide resonator is coupled to multiple unit cells, enabling phase correction at every nodes. After its initial demonstration in a Josephson traveling-wave parametric amplifier, we extended it to the KTWPAs platform. By combining the phase-matching capability of dcRPM with the intrinsic advantages of KTPWAs operation, we expect that this approach will provide a promising route toward broadband high-gain, quantum limited noise performance.