Broadband and fabrication-tolerant 3-dB couplers with topological valley edge modes  

作　　者：Guo-Jing Tang Xiao-Dong Chen Lu Sun Chao-Heng Guo Meng-Yu Li Zhong-Tao Tian Hou-Hong Chen Hong-Wei Wang Qi-Yao Sun Ying-Di Pan Xin-Tao He Yi-Kai Su Jian-Wen Dong 

机构地区：[1]School of Physics&State Key Laboratory of Optoelectronic Materials and Technologies,Sun Yat-sen University,Guangzhou 510275,China [2]State Key Laboratory of Advanced Optical Communication Systems and Networks,Department of Electronic Engineering,Shanghai Jiao Tong University,Shanghai 200240,China

出　　处：《Light(Science & Applications)》2024年第8期1623-1630,共8页光（科学与应用)（英文版）

基　　金：supported by National Key Research and Development Program of China(Grant No.2022YFA1404304);National Natural Science Foundation of China(Grant Nos.62035016,12274475,12074443,62105200);Guangdong Basic and Applied Basic Research Foundation(Grant Nos.2023B1515040023,2023B1515020072);Fundamental Research Funds for the Central Universities,Sun Yat-sen University(23lgbj021,23ptpy01)。

摘　　要：3-dB couplers,which are commonly used in photonic integrated circuits for on-chip information processing,precision measurement,and quantum computing,face challenges in achieving robust performance due to their limited 3-dB bandwidths and sensitivity to fabrication errors.To address this,we introduce topological physics to nanophotonics,developing a framework for topological 3-dB couplers.These couplers exhibit broad working wavelength range and robustness against fabrication dimensional errors.By leveraging valley-Hall topology and mirror symmetry,the photonic-crystal-slab couplers achieve ideal 3-dB splitting characterized by a wavelength-insensitive scattering matrix.Tolerance analysis confirms the superiority on broad bandwidth of 48 nm and robust splitting against dimensional errors of 20 nm.We further propose a topological interferometer for on-chip distance measurement,which also exhibits robustness against dimensional errors.This extension of topological principles to the fields of interferometers,may open up new possibilities for constructing robust wavelength division multiplexing,temperature-drift-insensitive sensing,and optical coherence tomography applications.

关 键 词：TOPOLOGICAL SPLITTING insensitive 

分 类 号：TN491[电子电信—微电子学与固体电子学]