High-efficiency and broadband on-chip electro-optic frequency comb generators

Developments in integrated photonics have led to stable, compact and broadband comb generators that support a wide range of applications including communications1, ranging2, spectroscopy3, frequency metrology4, optical computing5,6 quantum information7,8. Broadband combs can be generated electro-optical cavities, where light passes through phase modulator multiple times while circulating an resonator9–12. However, electro-optic are currently limited by low conversion efficiencies. Here we demonstrate with efficiency 30% span 132 nm, based on coupled-resonator platform thin-film lithium niobate13. We further show that, enabled the high efficiency, device acts as on-chip femtosecond pulse source (336 fs duration), which is important for nonlinear optics, sensing computing. As example, ultrafast high-power regime, simultaneous third-order nonlinearity effects. Our paves way practical provides investigate new regimes physics simultaneously involve nonlinearities. A double-ring-resonator niobate enables generation power nm.