Four-wave mixing photon pair generation statistics for a nonlinear microcavity with chaotic and pulsed excitation

The third-order process of spontaneous four-wave mixing (SFWM) has seen increasing use due to the CMOS-incompatibility and difficulty of integrating second-order material platforms, as well as due to the presence of third-order nonlinearities in common platforms. In integrated optics, SFWM's low efficiency is often compensated using on-chip nonlinear microcavities [1], however, excitation schemes for integrated microcavities remain bulky and complex, in particular because the sources of the excitation fields-pulsed and CW lasers-largely remain off-chip. The least complex and integratable excitation scheme for cavity resonances is the so-called `self-locked' scheme, wherein the microcavity is nested inside a longer cavity, with gain, and made to lase in the passband defined by a single microcavity resonance [2]. The consequent excitation field, however, exhibits uncharacterized chaotic pulse dynamics with likewise uncharacterized effects on the SFWM photon pair generation statistics. Here, we study the SFWM photon pair generation statistics in the chaotic pulsed regime associated with the self-locked excitation scheme. We use this scheme to excite SFWM in an integrated nonlinear microring resonator, and contrast the chaotic excitation against a pulsed actively mode-locked regime achieved using the same in-cavity components (Fig. 1a).