Parity-time symmetry in periodically curved optical waveguides

作     者：Zhang, Yan-Rong Zhang, Ze-Zheng Yuan, Jia-Qi Wang, Wei Wang, Lu-Qi Li, Zheng-Xian Xue, Rui-Dong Chen, Jing 

作者机构：Nankai Univ Sch Phys MOE Key Lab Weak Light Nonlinear Photon Tianjin 300071 Peoples R China Shanxi Univ Collaborat Innovat Ctr Extreme Opt Taiyuan 030006 Shanxi Peoples R China 

出 版 物：《OPTICS EXPRESS》 (Opt. Express)

年 卷 期：2018年第26卷第21期

页      面：27141-27152页

核心收录：

学科分类：070207[理学-光学] 07[理学] 08[工学] 0803[工学-光学工程] 0702[理学-物理学] 

基　　金：National Natural Science Foundation of China (NSFC) [11574162  11874228] 

主　　题：Coupled resonators Effective refractive index Numerical simulation Optical elements Quantum electronics Waveguides 

摘      要：The coupling strength between two parity-time (PT) symmetric resonators determines whether the PT phase is broken or not. Here we investigate the scenario that two optical waveguides are spatially curved so that they switch periodically between unbroken and broken PT phases. We show that the existence of locally broken PT phase does not necessarily render a broken phase to waves propagating inside. Criteria are proposed to characterize the collective dynamics of wave near the Brillouin zone (BZ) edge, toward the cases of a totally broken phase, a partially broken phase, or a totally unbroken phase. We also discuss the characteristics of two special kinds of exceptional points (EPs) at the BZ edge, and show that their field patterns are displaced by half a period with each other. Full-wave numerical simulation proves our analysis. Potential applications especially these associated with EPs are discussed. This study helps us to understand how the locally PT-symmetric related eigenstate influences the globally collective dynamics of wave in spatially periodic configuration. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement