Lithium niobate based photonic quantum devices and integration technology: opportunities and challenges

Lithium niobate has a wide light transparency range, high nonlinear-optic, electro-optic, acousto-optic and thermo-optic coefficients, as well as stable chemical properties, which makes it an ideal substrate material for photonic integration. In the field of quantum optics, a series of lithium niobate based integrated devices have been developed, which can enable the highly efficient generation, manipulation, frequency conversion, quantum storage and integrated single-photon detection of photon states, and has the potential for fully integrated photon frequency manipulation, deterministic multi-photon state generation and photon-photon interaction. This may push forward the development of fully functional integrated quantum optical circuits, which will further promote fundamental quantum physics studies and practical applications of quantum information technology. This paper will review the progress of lithium niobate based quantum integration, and its future opportunities and challenges.