Microfiber-Lithium Niobate on Insulator Hybrid Waveguides for Efficient and Reconfigurable Second-Order Optical Nonlinearity on a Chip

We present an optical microfiber-lithium niobate on insulator (MF-LNOI) hybrid waveguide for efficient second-order nonlinear processes. The structure combines the advantages of low-loss fiber and high-nonlinearity waveguide systems. We demonstrate the possibility of phase matching between fundamental and second harmonics in a wide spectral and dimensional range, and efficient second harmonic generation over sub-millimeter propagation distances, both of which are very attractive for high-density on-chip integration.