Entangled photon pair generation in a silicon nitride microresonator

Poster presented at conference Quantum2025 and (similar version) ICOLS2025. Entangled photon-pair generation in nonlinear media is a key resource for fundamental quantum physics, secure communications, quantum computing, and advanced information processing. While traditional platforms such as atomic transitions and cavity-enhanced bulk crystals have been widely used, photonic integrated circuits (PICs) offer a compact, low-power, and scalable alternative. In particular, silicon nitride microresonators exploiting cavity-enhanced spontaneous four-wave mixing provide efficient on-chip photon-pair sources compatible with CMOS technology and telecom infrastructure. In this work, we investigate photon-pair generation in a silicon nitride microring resonator with intrinsic Q~5×10^6, evanescently coupled to a straight waveguide (loaded QL~2.5×10^6). A resonance mode in the telecom C-band serves as the pump, producing three photon-pair modes symmetrically around the central wavelength. Photon correlations are analyzed via the g(1,1) function with superconducting nanowire single-photon detectors, while single-photon statistics are studied through the g(2) function. Results reveal the transition from thermal to Poissonian statistics and provide insight into the spectral bandwidth and coherence properties of the photons. This study highlights high-Q silicon nitride microresonators as promising narrowband sources of entangled photon pairs and demonstrates characterization methods complementary to spectroscopic analysis.