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.