This research explores the heterogeneous integration of lithium niobate (LiNbO₃) on silicon nitride (SiN) to enhance optical nonlinearities in photonic devices. By combining LiNbO₃’s exceptional electro-optic and nonlinear optical properties with SiN's low optical losses, this platform enables efficient frequency conversion, modulation, and signal processing. The project aims to develop scalable fabrication techniques and optimize interface quality for hybrid devices, paving the way for compact, high-performance photonic circuits in telecom, quantum computing, and sensing applications.