Leveraging thin film lithium niobate on insulator (LNOI) to enhance silicon nitrade platform: the LOLIPOP project.

Silicon nitride (SiN) photonic integrated circuits provide a strong passive foundation for integrated optics, offering very low propagation loss, broad transparency from the visible to the near infrared, and compatibility with scalable manufacturing [1-3]. Yet many system-level functions remain difficult to realize directly on SiN because the platform offers only weak native electro-optic, nonlinear, and optoelectronic response. LOLIPOP addresses this gap by using thin-film lithium niobate on insulator (LNOI) as a heterogeneous enhancement layer for the SiN platform. The resulting architecture merges micro-transfer-printed LNOI devices for high-speed modulation and nonlinear processing [4-7], flip-chip integration of GaAs gain chips for external-cavity lasers, and germanium photodiodes [8-9] for broadband detection, all coupled to a TriPleX SiN motherboard through low-loss interfaces. By combining these building blocks within one hybrid platform, LOLIPOP targets a set of demanding demonstrators spanning laser Doppler vibrometry, LiDAR, neuromorphic photonic computing, and squeezed-light generation for continuous-variable quantum photonics. Together, these demonstrators show how LNOI can expand SiN from a low-loss routing platform into a more capable multifunctional photonic system.