Silicon source of frequency-bin entangled photons.

We demonstrate an integrated source of frequency-entangled photon pairs on a silicon photonics chip. The emitter has a coincidence-to-accidental ratio exceeding 103. We prove entanglement by showing two-photon frequency interference with a visibility of 94.6% ± 1.1%. This result opens the possibility of on-chip integration of frequency-bin sources with modulators and the other active and passive devices available in the silicon photonics platform.