Nationwide Entanglement Distribution with Silicon Nanophotonic Chip

We developed a silicon chip capable of producing and delivering a detected rate of 460,000 pairs of entangled photons with a fidelity of 97.90(3)% fidelity. The entangled photons were transmitted over 155 km of fiber deployed across Singapore (66 dB loss), demonstrating a major advance in the capability of silicon nanophotonics for powering future quantum networks.