Superconducting parametric amplifiers have great promise for quantum-limitedreadout of superconducting qubits and detectors. Until recently, mostsuperconducting parametric amplifiers had been based on resonant structures,limiting their bandwidth and dynamic range. Broadband traveling-wave parametricamplifiers based both on the nonlinear kinetic inductance of superconductingthin films and on Josephson junctions are in development. By modifying thedispersion property of the amplifier circuit, referred to as dispersionengineering, the gain can be greatly enhanced and the size can be reduced. Wepresent two theoretical frameworks for analyzing and understanding suchparametric amplifiers: (1) generalized coupled-mode equations and (2) a finitedifference time domain (FDTD) model combined with a small signal analysis. Weshow how these analytical and numerical tools may be used to understand deviceperformance.
展开▼
