Low Power Kinetic Inductance Traveling wave parametric amplifiers

A quantum-limited amplification chain is attractive for any application that requires the detection of faint electromagnetic signals. Reading out arrays of superconducting resonators, calls for large bandwidth amplifiers in addition to having the lowest possible noise. At millikelvin temperatures, Kinetic Inductance Traveling-Wave Parametric Amplifiers (KI-TWPAs) working in 3-wave-mixing (3WM) and fabricated from a 20 nm thick NbTiN film have shown to operate close to the quantum limit [1]. However, they still require fairly high pump power, and the pump must be isolated from the device under test by components that unavoidably insert loss, thereby degrading the noise performance of the chain. An amplifier functioning with a lower pump power would necessitate fewer of these nefarious isolating components. One solution is to use thinner superconducting films, because the nonlinearity of the kinetic inductance increases with decreasing film's thickness. In this contribution, we report the design and the first characterization results of a 3WM KI-TWPA based on NbTiN films with a thickness less than 20 nm.