No abstract

Thin-film lithium niobate has emerged as an excellent, multifaceted platform for integrated photonics and opto-electronics, in both classical and quantum domains. We introduce a novel, to the best of our knowledge, dual-capacitor electrode layout for an efficient interface between electrical and optical signals on this platform. It significantly enhances the electro-optical modulation efficiency to an exceptional voltage–length product of 0.64 V ⋅ c m , thereby lowering the required electric power by many times. This technique can boost the performance of growing applications at the interface of integrated electronics and optics, such as microwave photonics, frequency comb generation, and telecommunication transmission.

Thin‐film lithium niobate (TFLN) is superior for integrated nanophotonics due to its outstanding properties in nearly all aspects: strong second‐order nonlinearity, fast and efficient electro‐optic effects, wide transparency window, and little two photon absorption and free carrier scattering. Together, they permit highly integrated nanophotonic circuits capable of complex photonic processing by incorporating disparate elements on the same chip. Yet, there has to be a demonstration that synergizes those superior properties for system advantage. Here, such a chip that capitalizes on TFLN's favorable ferroelectricity, high second‐order nonlinearity, and strong electro‐optic effects is demonstrated. It consists of a monolithic circuit integrating a Z‐cut, quasi‐phase matched microring with high quality factor and a phase modulator used in active feedback control. By Pound–Drever–Hall locking, it realizes stable frequency doubling at about 50% conversion with only milliwatt pump power. This demonstration addresses a long‐outstanding challenge facing cavity‐based optical processing, including frequency conversion, frequency comb generation, and all‐optical switching, whose stable performance is hindered by photorefractive or thermal effects. These results further establish TFLN as an excellent material capable of optical multitasking, as desirable to build multi‐functional chip devices.

We demonstrate an electro-optic modulator on thin-film lithium niobate using a novel dual-capacitor scheme. The voltage-length product reaches 0.64 volt × cm, thus substantially reducing the driving electric power.

Thin-film lithium niobate (TFLN) is superior for integrated nanophotonics due to its outstanding properties in nearly all aspects: strong second-order nonlinearity, fast and efficient electro-optic effects, wide transparency window, and little two photon absorption and free carrier scattering. Together, they permit highly integrated nanophotonic circuits capable of complex photonic processing by incorporating disparate elements on the same chip. Yet, there has to be a demonstration that synergizes those superior properties for system advantage. Here we demonstrate such a chip that capitalizes on TFLN's favorable ferroelectricity, high second-order nonlinearity, and strong electro-optic effects. It consists of a monolithic circuit integrating a Z-cut, quasi-phase matched microring with high quality factor and a phase modulator used in active feedback control. By Pound-Drever-Hall locking, it realizes stable frequency doubling at about 50% conversion with only milliwatt pump, marking the highest by far among all nanophotonic platforms with milliwatt pumping. Our demonstration addresses a long-outstanding challenge facing cavity-based optical processing, including frequency conversion, frequency comb generation, and all-optical switching, whose stable performance is hindered by photorefractive or thermal effects. Our results further establish TFLN as an excellent material capable of optical multitasking, as desirable to build multi-functional chip devices.