Exploring New Techniques for Superconducting Kinetic Inductance Parametric Amplifiers

Superconducting parametric amplifiers are able to amplify a signal with zero added noise in theory. They are created from transmission lines with nonlinear properties or elements. But this relatively new area of research still has many opportunities for exploring new avenues. While CPW (Co-Planar Waveguide) is still the most common transmission medium chosen due to its simplicity of fabrication, using a microstrip medium would allow for more flexibility, complexity, and performance in designing these amplifier circuits. Some groups use microstrip circuits already, but with an amorphous dielectric which will contribute more noise, so a fabrication method for using SOI (Silicon On Insulator) is presented. In order to reduce the long transmission line lengths required for sufficient gain and to provide an alternative for creating bandgaps, a model for loading the amplifying transmission line with capacitive stubs is discussed. Since placing these stubs in close proximity causes them to electromagnetically couple, a technique for simplifying the modeling of an arbitrarily long periodic coupled structure is offered. Given that current superconductors require a cryogenic system, the complexity of designing and measuring in these conditions are described. In order to test high frequency devices at cryogenic temperatures, a w-band four-wave mixing parametric amplifier test system in a milliKelvin dilution refrigerator has been prepared.