Numerical analysis of a three-wave-mixing Josephson traveling-wave parametric amplifier with engineered dispersion loadings

Abstract

The recently proposed Josephson traveling-wave parametric amplifier (JTWPA) based on a ladder transmission line consisting of radio-frequency superconducting quantum interference devices and exploiting three-wave mixing has great potential in achieving both a gain of 20 dB and a flat bandwidth of at least 4 GHz. To realize this concept in practical amplifiers, we model the advanced JTWPA circuit with periodic modulation of the circuit parameters (engineered dispersion loadings), which allow the basic mixing process, i.e., ω s = ω p - ω i, where ω s, ω p, and ω i are the signal, the pump, and the idler frequencies, respectively, and efficiently suppress propagation of unwanted higher tones, including ω 2 p = 2 ω p, ω p + s = ω p + ω s, ω p + i = ω p + ω i, etc. The engineered dispersion loadings allow achieving a sufficiently wide 3 dB-bandwidth from 3 to 9 GHz combined with a reasonably small ripple (± 2 dB) in the gain-vs-frequency dependence.