Classical and Quantum Experiments Using Hybrid Si3N₄-LiNbO₃ Photonic Chip

We fabricated various optical devices on a hybrid Si3N4–LiNbO3 platform for integrated quantum photonic circuits and observed Hong-Ou–Mandel (HOM) quantum interference. Strip-loaded waveguides were prepared via Si3N4 deposition on LiNbO3. Consequently, fundamental building blocks for quantum photonics, such as ring resonators, various beam splitters, and Mach-Zehnder interferometers, were fabricated and tested. Using 50:50 beam splitters, we observed HOM quantum interference and achieved a visibility of $96.6~\pm ~1.2$ % after the subtraction of accidental counts. More advanced quantum-integrated devices are expected to be realized using the proposed hybrid platform.