Hybrid quantum networks rely on faithful quantum state transfer between disparate physics elements operating at dissimilar frequencies. Quantum frequency conversion bridges their frequency gaps by coherently manipulating the carrier frequency while maintaining the quantum correlations. The efficiency of frequency conversion is dictated by photon-photon interaction in a nonlinear optical media which is typically weak. In this talk, I will show material and device engineering on an integrated photonic platform where the nonlinear photon-photon coupling can be greatly enhanced. Specifically, I will show (1) coherent conversion of light between visible and telecom wavelengths; (2) noise-free frequency shift of photon within telecom band; and (3) microwave-to-optical frequency conversion that promises to link superconducting quantum circuits and room temperature fiber-coupled quantum systems.