Kerr-enhanced amplification of three-wave mixing and emergent masing regimes

Abstract

Integrated optical microresonators exploiting either second-order (${\chi }^{(2)}$) or third-order (${\chi }^{(3)}$) nonlinearities have become key platforms for frequency conversion, low-noise microwave photonics, and quantum entanglement generation. Here, we present an analytic theory of Kerr-enhanced three-wave mixing amplification in an electro-optic microresonator with both ${\chi }^{(2)}$ and ${\chi }^{(3)}$ nonlinearities. We demonstrate that Kerr dressing hybridizes the optical sidebands, renormalizing the ${\chi }^{(2)}$ couplings and detunings. As a result the system exhibits gain in regions where analogous bare ${\chi }^{(2)}$ or ${\chi }^{(3)}$ amplifiers are subthreshold. Time-domain Langevin simulations confirm this threshold reduction, mapping a practical design window for experiments.

15 pages, 4 figures, containing supplemental materials,