On-chip photon-pair generation in a silica microtoroidal cavity

Abstract

Microcavities with high Q factor and small mode volume have the potential to be efficient and compact sources of photon pairs. Here, we demonstrate on-chip photon-pair generation by spontaneous four-wave mixing in a silica microtoroidal cavity and obtain a coincidence-to-accidental ratio of 7.4 ± 0.1 with a pump power of 46 µ W. The heralded photons also exhibit antibunching characterized by autocorrelation function values of g c ( 2 ) ( 0 ) = 0.57 ± 0.03 < 1 . Comparing with a scaling model, the main noise source is found to be spontaneous Raman scattering in the cavity. This work opens a new possible means for realizing integrated nonclassical photon sources based on silica photonic circuits toward scalable quantum technologies.