Lithium niobate-on-insulator photonics for optical quantum technology

Integrated photonic circuits have many applications in quantum information science, from quantum transduction and communication, to linear optical quantum computing. While silicon photonics has been successful in demonstrating small-scale quantum information processing, there are fundamental limitations of the platform for quantum technology. Lithium niobate-on-insulator (LNOI) is a breakthrough photonics technology that takes the excellent optical properties of lithium niobate, including electro-optic modulation and a second order nonlinearity, to a high index contrast platform for dense circuits. Here, we introduce our efforts towards optical quantum information processing with LNOI photonics. We first discuss our work on efficient photon-pair generation via spontaneous parametric down-conversion in periodically poled LNOI waveguides with tailored spectral correlations. We then demonstrate on-chip generation and quantum interference of single photons in programmable photonic circuit. Finally, we discuss our work towards applying this technology for quantum key distribution, and the outlook for LNOI quantum photonics for large-scale optical quantum computation.