Traveling Wave Parametric Amplifiers and Other Nonlinear Kinetic Inductance Devices

The microwave frequency range is home to a large amount of cosmologically crucial signals including the cosmic microwave background, emission from high redshift galaxies, and spectral absorption from interstellar dust. In addition to this wealth of scientifically interesting signals, various cutting-edge detector technologies such as microwave kinetic inductance detectors also operate at those frequencies. Both of these areas would greatly benefit from improved readout electronics, which would ideally include broadband, high gain, and low noise amplification. These conditions are generally quite difficult to achieve simultaneously, and have driven the development of a large number of innovative technological solutions. Recently, superconducting traveling wave parametric amplifiers have emerged as a promising candidate for simultaneously meeting the amplification requirements in the microwave regime. In this thesis, we present further developments of traveling wave parametric amplifiers and other devices based on the nonlinear kinetic inductance of NbTiN transmission lines. The design techniques used for dispersion engineering and impedance matching are very robust, allowing for straightforward alterations to produce amplifiers with bandwidths centered at vastly different frequencies. The majority of our designs focus on the low frequency region from 2 to 12 GHz, where we demonstrate broadband amplifiers with 20 to 30 dB gain, quantum-limited noise, and minimal losses enabling vacuum noise squeezing. The excellent gain and noise performance of one such amplifier is further demonstrated by its use in the readout of a hidden photon dark matter search that sets new limits on the allowable kinetic mixing coupling. One such device was also operated in an up-conversion mode to demonstrate nearly perfect photon conversion efficiency of a narrowband signal near 1.75 GHz to a 12.55 GHz output. At higher frequencies, similar devices are shown to produce gain across over three octaves of bandwidth extending up to 34 GHz and a parametric amplifier operating in the W band. Utilizing the change in phase velocity in our transmission lines with applied current, we build and test a Fourier transform interferometer. We further present a smaller, optimized design that could someday enable the construction of a single-wafer kilopixel array of spectrometers for spatially resolved measurements of the spectral distortions in the cosmic microwave background.