Asymmetric frequency multiplexing topological devices based on a floating edge band  

作　　者：JIAJUN MA CHUNMEI OUYANG YUTING YANG DONGYANG WANG HONGYI LI LI NIU YI LIU QUAN XU YANFENG LI ZHEN TIAN JIAGUANG HAN WEILI ZHANG 

机构地区：[1]Center for Terahertz Waves and College of Precision Instrument and Optoelectronics Engineering,and Key Laboratory of Optoelectronics Information and Technology,Tianjin University,Tianjin 300072,China [2]School of Materials Science and Physics,China University of Mining and Technology,Xuzhou 221116,China [3]Optoelectronics Research Centre,University of Southampton,Southampton SO171BJ,UK [4]Guangxi Key Laboratory of Optoelectronic Information Processing,School of Optoelectronic Engineering,Guilin University of Electronic Technology,Guilin 541004,China [5]School of Electrical and Computer Engineering,Oklahoma State University,Stillwater,Oklahoma 74078,USA

出　　处：《Photonics Research》2024年第6期1201-1212,共12页光子学研究（英文版）

基　　金：National Natural Science Foundation of China(62175180,62027820,62005193,11874245,12004425);Natural Science Foundation of Jiangsu Province(BK20200630).

摘　　要：Topological photonics provides a platform for robust energy transport regardless of sharp corners and defects.Recently,the frequency multiplexing topological devices have attracted much attention due to the ability to separate optical signals by wavelength and hence the potential application in optical communication systems.Existing frequency multiplexing topological devices are generally based on the slow light effect.However,the resulting static local spatial mode or finely tuned flat band has zero-group velocity,making it difficult for both experimental excitation and channel out-coupling.Here,we propose and experimentally demonstrate an alternative prototype of asymmetric frequency multiplexing devices including a topological rainbow and frequency router based on floating topological edge mode(instead of localized ones);hence the multiple wavelength channels can be collectively excited with a point source and efficiently routed to separate output ports.The channel separation in our design is achieved by gradually tuning the band gap truncation on a topological edge band over a wide range of frequencies.A crucial feature lies in that the topological edge band is detached from bulk states and floating within the upper and lower photonic band gaps.More interestingly,due to the sandwiched morphology of the edge band,the top and bottom band gaps will each truncate into transport channels that support topological propagation towards opposite directions,and the asymmetrical transportation is realized for the frequency multiplexing topological devices.

关 键 词：tuning FLOATING hence 

分 类 号：TN929.1[电子电信—通信与信息系统]