A silicon-chip source of bright photon-pair comb

Integrated quantum photonics relies critically on the purity, scalability, integrability, and flexibility of a photon source to support diverse quantum functionalities on a single chip. Up to date, it remains an open challenge to realize an efficient monolithic photon-pair source for on-chip application. Here we report a device on the silicon-on-insulator platform that utilizes dramatic cavity enhanced four-wave mixing in a high-Q silicon microdisk resonator. The device is able to produce high-purity photon pairs in a comb fashion, with an unprecedented spectral brightness of $6.24 \times 10^7 {\rm pair/s/mW^2/GHz}$ and photon-pair correlation with a coincidence-to-accidental ratio of $1386 \pm 278$ while pumped with a continuous-wave laser. The superior performance, together with the structural compactness and CMOS compatibility, opens up a great avenue towards quantum silicon photonics with unprecedented capability of multi-channel parallel information processing for both integrated quantum computing and long-haul quantum communication.