Optical frequency conversion based on the second-order nonlinearity(χ^((2))) only occurs in anisotropic media(or at interfaces) and thus is intrinsically polarization-dependent. But for practical applications, polari...Optical frequency conversion based on the second-order nonlinearity(χ^((2))) only occurs in anisotropic media(or at interfaces) and thus is intrinsically polarization-dependent. But for practical applications, polarization-insensitive or independent operation is highly sought after. Here, by leveraging polarization coupling and second-order nonlinearity, we experimentally demonstrate a paradigm of TE/TM polarization-independent frequency upconversion, i.e., sum frequency generation, in the periodically poled lithium niobate-on-insulator ridge waveguide. The cascading of quasi-phase-matched polarization coupling and nonlinear frequency conversion is exploited. With a proper transverse electric field, TE and TM mode fundamental waves can be frequency-upconverted with an equal efficiency in the frequency converter. The proposed method may find ready application in all-optical wavelength conversion and upconversion detection technologies.展开更多
基金supported by the National Natural Science Foundation of China(Nos.12074252,12192252,62005159,62022058,61705127,and 12104289)the National Key Research and Development Program of China(No.2018YFA0306301)+2 种基金the Shanghai Municipal Science and Technology Major Project(No.2019SHZDZX01-ZX06)the Shanghai Rising-Star Program(No.20QA1405400)the Yangyang Development Fund.
文摘Optical frequency conversion based on the second-order nonlinearity(χ^((2))) only occurs in anisotropic media(or at interfaces) and thus is intrinsically polarization-dependent. But for practical applications, polarization-insensitive or independent operation is highly sought after. Here, by leveraging polarization coupling and second-order nonlinearity, we experimentally demonstrate a paradigm of TE/TM polarization-independent frequency upconversion, i.e., sum frequency generation, in the periodically poled lithium niobate-on-insulator ridge waveguide. The cascading of quasi-phase-matched polarization coupling and nonlinear frequency conversion is exploited. With a proper transverse electric field, TE and TM mode fundamental waves can be frequency-upconverted with an equal efficiency in the frequency converter. The proposed method may find ready application in all-optical wavelength conversion and upconversion detection technologies.
