Time-correlated photons from an In0.5Ga0.5P photonic crystal cavity on a silicon chip

Abstract

Time-correlated photon pairs are generated by triply resonant four-wave-mixing in an ${\mathrm{In}}_{0.5}{\mathrm{Ga}}_{0.5}\mathrm{P}$ photonic crystal cavity. Maximal efficiency is reached by actively compensating for the residual spectral misalignment of the cavity modes. The generation rate reaches 5 MHz in cavities with a $Q$-factor $\ensuremath{\approx}4\ifmmode\times\else\texttimes\fi{}{10}^{4}$, more than one order of magnitude larger than what is measured using ring resonators with similar $Q$ factors fabricated on the same chip. The photonic crystal source is integrated on a Si photonic circuit, an important asset for applications in quantum technologies.