Rui Ming Chua

We demonstrated a configurable on-chip entangled photon source for BBM92 quantum key distribution (QKD) networks. Built on a scalable silicon-on-insulator (SOI) platform, our design incorporates tunable ring resonators. These allow precise, on-chip adjustment of the quality factor (Q-factor), which is central to optimizing the brightness and noise of the source. Our extensive characterization shows this source achieves a coincidence-to-accidental ratio (CAR) of 48239, $g^2(0)$ of $6.8\times10^{-4}$ and raw coincidence rate of 212k counts/second. This exceeds performance reported in the literature. This performance directly translates to higher secure key rates, lower QBER and QKD robustness. The ability to fine-tune source parameters provides flexibility, allowing adaptation to diverse network conditions and optimization for specific QKD applications. This research marks a step toward creating compact, efficient, and reconfigurable entangled sources for practical and scalable quantum communication.