On-Chip Generation and Manipulation of Entangled Photons Based on Reconfigurable Lithium-Niobate Waveguide Circuits

A consequent tendency toward high-performance quantum information processing is to develop the fully integrated photonic chip. Here, we report the on-chip generation and manipulation of entangled photons based on reconfigurable lithium-niobate waveguide circuits. By introducing a periodically poled structure into the waveguide circuits, two individual photon-pair sources with a controllable electro-optic phase shift are produced within a Hong-Ou-Mandel interferometer, resulting in a deterministically separated identical photon pair. The state is characterized by $92.9\pm 0.9\%$ visibility Hong-Ou-Mandel interference. The photon flux reaches $\sim 1.4\times {10}^7\text{pairs}{\mathrm{nm}}^{-1}{\mathrm{mW}}^{-1}$. The whole chip is designed to contain nine similar units to produce identical photon pairs spanning the telecom $C$ and $L$ band by the flexible engineering of nonlinearity. Our work presents a scenario for on-chip engineering of different photon sources and paves the way to fully integrated quantum technologies.