# Broadband parametric amplifiers based on nonlinear kinetic inductance artificial transmission lines

## TL;DR

This paper introduces broadband superconducting parametric amplifiers using kinetic inductance in artificial transmission lines, achieving high gain and bandwidth with improved design features over traditional CPW-based amplifiers.

## Contribution

The paper presents novel amplifier designs employing phase matching techniques in artificial transmission lines with kinetic inductance, offering advantages like intrinsic impedance matching and harmonic suppression.

## Key findings

- Achieved 15 dB gain over several GHz bandwidth
- Demonstrated two phase matching techniques in amplifier designs
- Realized compact amplifiers with improved performance metrics

## Abstract

We present broadband parametric amplifiers based on the kinetic inductance of superconducting NbTiN thin films in an artificial (lumped-element) transmission line architecture. We demonstrate two amplifier designs implementing different phase matching techniques: periodic impedance loadings, and resonator phase shifters placed periodically along the transmission line. Our design offers several advantages over previous CPW-based amplifiers, including intrinsic 50 ohm characteristic impedance, natural suppression of higher pump harmonics, lower required pump power, and shorter total trace length. Experimental realizations of both versions of the amplifiers are demonstrated. With a transmission line length of 20 cm, we have achieved gains of 15 dB over several GHz of bandwidth.