Traveling-wave parametric amplifier with three-wave mixing in superconducting transmission line with embedded rf-SQUIDs
Alexander B Zorin
Abstract
We develop a concept of traveling-wave Josephson parametric amplifier based on a ladder-type superconducting transmission line containing serial array of one-junctions SQUIDs. The circuit operates in a three-wave mixing mode and exploits both quadratic and cubic (Kerr) nonlinearities in the current-phase relation of the SQUIDs controlled by external magnetic flux. These two types of nonlinearities allow efficient three-wave mixing and perfect phase matching, respectively. The transmission line exhibits a power gain with exponential dependence on its length (number of cells $N$) in the widest frequency range, $0 \lesssim f_s, f_i \lesssim f_p$, where $f_s$, $f_i$ and $f_p$ are the signal, idler and pump frequencies, respectively, obeying relation $f_s + f_i = f_p$. Estimation of the amplifier characteristics with typical experimental parameters, number of cells $N$ = 700, length of 28 mm and pump frequency of 12.5 GHz yields a flat (-3 dB) gain of about 20 dB in the bandwidth from 3.35 GHz to 9.15 GHz and a saturation power of -90 dBm.