Optical source of individual pairs of colour-conjugated photons

We theoretically demonstrate that Kerr nonlinearity in optical circuits can lead to both resonant four-wave mixing and photon blockade, which can be used for high-yield generation of high-fidelity individual photon pairs with conjugated frequencies. We propose an optical circuit, which, in the optimal pulsed-drive regime, would produce photon pairs at the rate up to 5 × 105  s −1 (0.5 pairs per pulse) with $${{\boldsymbol{g}}}^{{\bf{(2)}}}{\bf{(0)}}{\boldsymbol{ < }}{{\bf{10}}}^{-{\bf{2}}}$$ g (2) (0) < 10 − 2 for one of the conjugated frequencies. We show that such a scheme can be utilised to generate colour-entangled photons.