Superspontaneous four-wave mixing in a sequence of lossy ring resonators

In this paper, we build upon our previous study on super spontaneous four-wave mixing (SFWM) in single-channel side-coupled integrated spaced sequence of resonators (SCISSOR) by investigating the impact of loss. Our results show that, in the presence of loss, superradiant photon-pair generation in single-channel sequences is achievable only when the resonators are either deeply over or undercoupled. We then consider super-SFWM in double-channel sequences composed of ring resonators in the add-drop configuration. We show that this configuration can also exhibit superradiant emission once the ring resonators are strongly over-coupled. We study the spectral correlations of the generated pairs in the regime of pulsed pump excitation and find that without being affected by loss, double-channel configuration can generate uncorrelated photon pairs. Our calculations suggest that in the presence of undesirable nonlinear loss mechanisms ring resonator sequences can be employed to achieve a higher generation rate.