Hurley, Cooper2022-10-272022-10-272022https://udspace.udel.edu/handle/19716/31535For the past 30 years, the Silicon on Insulator (SOI) platform has dominated the field of photonic integrated circuits. Silicon is hugely abundant, optically capable, and has had decades of research performed by the semiconductor industry. However, due to fundamental material properties, silicon has limitations to its capability in upcoming communications applications. High third-order nonlinearity leads to excessive losses at high RF and optical power and the lack of a second-order nonlinearity limits its usage to digital modulation. Therefore, a new material platform must be explored in order to perform analog modulation. In this case, lithium niobate (LN) exceeds where silicon underperforms. With a transparency window that extends deep into the visible spectrum, high second-order, and low third-order nonlinearity, lithium niobate is ideal for high- speed linear analog modulators. While mode size in bulk lithium niobate prevents dense integration on-chip, its thin-film form yields superior confinement. When paired with silicon nitride in a ridge loaded architecture, mode size is decreased by a factor of almost 100x over titanium diffused bulk LN waveguides. Additionally, while lithium niobate is not a readily used material in semiconductor foundries, silicon nitride is, which provides easy manufacturing of silicon nitride features on the thin-film LN. Devices that utilize the hybrid thin-film lithium niobate silicon nitride platform have been explored in literature, however, there are design factors that must be addressed when considering monolithic integration. This thesis investigates design parameters that help improve the integration of multiple devices onto a single hybrid chip. Studies, including waveguide transmission efficiency, minimum band radius, and waveguide crossing optimization, are explored in two different potential hybrid architectures.Lithium niobatePhotonic integrated circuitsPhotonicsSilicon nitrideWaveguide crossingThesis13489472432022-08-10en