On-chip dense quantum frequency comb generation via SFWM in an AlGaAs-on-insulator resonator

Bright and broadband integrated photon sources at telecom wavelengths are essential for quantum communication and information processing. Materials with high nonlinear refractive index (n₂), such as aluminum gallium arsenide (AlGaAs), enable efficient nonlinear interactions at low excitation powers in integrated cavities. Here, we demonstrate a broadband quantum frequency comb (QFC) in a low free spectral range (FSR) (45 GHz) aluminum gallium arsenide on insulator (AlGaAsOI) resonator, with up to 40 pairwise frequency-correlated modes across a 1.97 THz bandwidth in the C-band. The dense mode spacing enables scalable frequency multiplexing and frequency-bin encoding within a compact device operating at a low excitation power of 6.33 µW. The measured joint-spectral intensity (JSI) is well reproduced by a theoretical model, enabling predictive control of spectral correlations across the generated QFC. The moderate Q-factor provides a tradeoff between nonlinear enhancement, broadband phase-matching, and number of accessible modes, supporting dense multimode operation over a large spectral range. These results highlight the potential of AlGaAsOI resonators for scalable low-power QFC sources.