Integrated quantum photonics requires bright, high-fidelity photon-pair sources capable of spectral multiplexing, correlation control, and circuit-compatible extraction. Cavity-enhanced spontaneous parametric down-conversion (SPDC) increases pair generation, but triply resonant operation imposes stringent pump-signal-idler spectral-alignment constraints. Moreover, the trade-off between intrinsic generation and coincidence-to-accidental ratio (CAR) does not capture the usable output flux, which depends on photon extraction. Here, we demonstrate a single-pass-pumped, resonator-enhanced quantum frequency comb (QFC) source based on a periodically poled lithium niobate photonic-crystal Fabry-P
eˊrot microresonator. The device yields intrinsic and loaded brightnesses of 69.9 and 1.88 MHz/
μW, respectively, and a maximum CAR of 16,000. Frequency-resolved measurements reveal 461 cavity-defined bins spanning 1495-1570 nm, and loaded spectral brightness approaching
4.29×109 pairs/(s
⋅mW
⋅nm). Heralded autocorrelation measurements yield a second-order autocorrelation
gH(2)(0) as low as
4.0×10−4 for a selected high-CAR cavity-defined bin pair. In particular, tuning the single-pass pump deterministically selects correlated frequency-bin pairings within the fixed QFC grid while preserving brightness and pairwise coincidence rates. We further separate intrinsic generation from output photon-pair flux, revealing the loaded-brightness-CAR relation. Together, pump-selectable bin pairing and extraction-aware loading point to tailored SPDC QFCs as chip-integrated nonclassical light resources for multichannel quantum-state transport and information processing.
Photonic entanglement distribution with wavelength division multiplexing (WDM) technology is a promising method for increasing capacity in quantum communication. So far, various experiments [1], [2] have been actively conducted by using broadband entangled photon pairs based on spontaneous parametric down-conversion (SPDC) with WDM-compatible spectral filters. However, the separation of broadband photon pairs over the channels inevitably wastes a large amount of photon energy for sufficient suppression of channel crosstalk, which causes photon pairs to have a low brightness. The cavity-enhanced SPDC can be used to overcome this problem. Because the generated photon pairs are gathered into resonant peaks with a spectral spacing determined by the cavity, the joint spectrum of the photon pairs becomes a comb-like structure called a biphoton frequency comb [3–5]. Consequently, by designing the free spectral range (FSR) of cavity to be the same as the channel spacing of the WDM channels, efficient and precise extraction of photon pairs from a biphoton frequency comb to each channel of the WDM system can be achieved [6].