Kerr Frequency Comb Interaction with Raman, Brillouin, and Second Order Nonlinear Effects

Kerr optical frequency comb as a novel microcomb source has found a variety of key applications from fundamental research to engineering applications. Generation of such microcombs require resonator platforms with small mode volumes and high quality factors, where the interaction of light and matter is resonantly enhanced. In these platforms, other nonlinear photonic effects can be simultaneously excited and interact with Kerr frequency combs. In this review, the focus is on recent progresses on the microcomb development involving its interaction with Raman, Brillouin scattering, and second-order nonlinear processes such as second harmonic generation (SHG). The resulting transfer of Kerr frequency combs into other spectral windows as referred to Kerr–Raman, Kerr–Brillouin, Kerr–SHG combs is introduced. Additionally, other emerging novel microcombs in microresonators with second-order nonlinearity including electro-optical modulation microcombs and quadratic microcombs are reviewed. Challenges and opportunities brought along are also discussed.