Efficient photon-pair generation in layer-poled lithium niobate nanophotonic waveguides  

作　　者：Xiaodong Shi Sakthi Sanjeev Mohanraj Veerendra Dhyani Angela Anna Baiju Sihao Wang Jiapeng Sun Lin Zhou Anna Paterova Victor Leong Di Zhu 

机构地区：[1]A*STAR Quantum Innovation Centre(Q.InC),Institute of Materials Research and Engineering(IMRE),Agency for Science,Technology and Research(A*STAR),Singapore 138634,Singapore [2]Department of Physics,National University of Singapore,Singapore 117542,Singapore [3]Department of Materials Science and Engineering,National University of Singapore,Singapore 117575,Singapore [4]Centre for Quantum Technologies,National University of Singapore,Singapore 117543,Singapore

出　　处：《Light(Science & Applications)》2024年第11期2847-2856,共10页光（科学与应用)（英文版）

基　　金：supported by the National Research Foundation(NRF2022-QEP2-01-P07,NRF-NRFF15-2023-0005);A*STAR(C230917005,M23M7c0125);Singapore,and Centre for Quantum Technologies(CQT bridging fund).

摘　　要：Integrated photon-pair sources are crucial for scalable photonic quantum systems.Thin-film lithium niobate is a promising platform for on-chip photon-pair generation through spontaneous parametric down-conversion(SPDC).However,the device implementation faces practical challenges.Periodically poled lithium niobate(PPLN),despite enabling flexible quasi-phase matching,suffers from poor fabrication reliability and device repeatability,while conventional modal phase matching(MPM)methods yield limited efficiencies due to inadequate mode overlaps.Here,we introduce a layer-poled lithium niobate(LPLN)nanophotonic waveguide for efficient photon-pair generation.It leverages layer-wise polarity inversion through electrical poling to break spatial symmetry and significantly enhance nonlinear interactions for MPM,achieving a notable normalized second-harmonic generation(SHG)conversion efficiency of 4615%W^(−1)cm^(−2).Through a cascaded SHG and SPDC process,we demonstrate photon-pair generation with a normalized brightness of 3.1×10^(6)Hz nm^(−1)mW^(−2)in a 3.3 mm long LPLN waveguide,surpassing existing onchip sources under similar operating configurations.Crucially,our LPLN waveguides offer enhanced fabrication reliability and reduced sensitivity to geometric variations and temperature fluctuations compared to PPLN devices.We expect LPLN to become a promising solution for on-chip nonlinear wavelength conversion and non-classical light generation,with immediate applications in quantum communication,networking,and on-chip photonic quantum information processing.

关 键 词：WAVEGUIDE WAVEGUIDES LITHIUM 

分 类 号：O43[机械工程—光学工程]