Dispersion-Suppressed Mode Depletion by Exceptional Points for On-Chip Nonlinear Optics

Dispersion-suppressed mode depletion in a resonant cavity is usually challenging due to the entan-glement of amplitude and phase response dictated by the Kramers-Kronig relationship. In this study, we examine the dispersion-suppressed mode depletion induced by parity-time-(PT-) symmetric dual resonators by taking advantage of the exotic property at the exceptional point (EP). We show that this technique can modify the linear spectrum of an optical resonator for relaxed phase-matching condi-tions in nonlinear optics, thus profoundly altering the nonlinear behavior of integrated Kerr combs. Indeed, dissipation-induced modulation instability (MI) is predicted and numerically verified in nor-mal group-velocity dispersion (GVD) microresonators, and the single-soliton-generation probability is greatly enhanced in the anomalous GVD regime. The merging of two vibrant disciplines, i.e., non-Hermitian optics and nonlinear optics, especially Kerr microcombs, can deepen our understand-ing of non-Hermitian optical frequency combs and opens broad applications ranging from fiber-optic communications, microwave photonics, and ultrafast optics to quantum state manipulations.