Generation of photon pairs by stimulated emission in ring resonators

Third-order parametric downconversion (TOPDC) describes a class of nonlinear interactions in which a pump photon is converted into a photon triplet. This process can occur spontaneously or it can be stimulated by seeding fields. Here we show that stimulated TOPDC (StTOPDC) can be exploited for the generation of quantum correlated photon pairs. We model StTOPDC in a microring resonator, predicting observable pair generation rates in a microring engineered for third-harmonic generation, and we examine the peculiar features of this approach when compared with second-order spontaneous parametric downconversion and spontaneous four-wave mixing. We conclude that if the experimental difficulties associated with implementing StTOPDC can be overcome, it may soon be possible to demonstrate this process in resonant integrated devices.