Broadband SNAIL parametric amplifier with microstrip impedance transformer
Daria A. Ezenkova, Dmitry O. Moskalev, Nikita S. Smirnov, Аnton I. Ivanov, Aleksei R. Matanin, Victor I. Polozov, Vladimir V. Echeistov, Elizaveta I. Malevannaya, Andrey A. Samoylov, E. V. Zikiy, Ilya A. Rodionov
Abstract
Josephson parametric amplifiers are an important part of a modern superconducting quantum computing platform and squeezed quantum states generation devices. Traveling wave and impedance-matched parametric amplifiers provide broad bandwidth for high-fidelity single-shot readout of multiple qubit superconducting circuits. Here, we present a quantum-limited 3-wave-mixing parametric amplifier based on superconducting nonlinear asymmetric inductive elements (SNAILs), whose useful bandwidth is enhanced with an on-chip two-section impedance-matching circuit based on microstrip transmission lines. The amplifier dynamic range is increased using an array of 67 SNAILs with 268 Josephson junctions, forming a nonlinear quarter-wave resonator. Operating in a current-pumped mode, we experimentally demonstrate an average gain of 17 dB across 300 MHz bandwidth, along with an average saturation power of –100 dBm, which can go as high as −97 dBm with quantum-limited noise performance. Moreover, the amplifier can be fabricated using a simple technology with just one e-beam lithography step.