Li Lingzhi, Cao Yuan, Zhi Yanyan, Zhang Jiejun, Zou Yuting, Feng Xinhuan, Guan Bai-Ou, Yao Jianping
Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, Guangzhou, 511442 China.
Microwave Photonics Research Laboratory, School of Electrical Engineering and Computer Science, University of Ottawa, Ottawa, ON K1N 6N5 Canada.
Light Sci Appl. 2020 Sep 27;9:169. doi: 10.1038/s41377-020-00407-3. eCollection 2020.
Parity-time (PT) symmetry has attracted intensive research interest in recent years. PT symmetry is conventionally implemented between two spatially distributed subspaces with identical localized eigenfrequencies and complementary gain and loss coefficients. The implementation is complicated. In this paper, we propose and demonstrate that PT symmetry can be implemented between two subspaces in a single spatial unit based on optical polarimetric diversity. By controlling the polarization states of light in the single spatial unit, the localized eigenfrequencies, gain, loss, and coupling coefficients of two polarimetric loops can be tuned, leading to PT symmetry breaking. As a demonstration, a fiber ring laser based on this concept supporting stable and single-mode lasing without using an ultranarrow bandpass filter is implemented.
近年来，宇称-时间（PT）对称性引起了广泛的研究兴趣。传统上，PT对称性是在两个具有相同局域本征频率以及互补增益和损耗系数的空间分布子空间之间实现的。这种实现方式很复杂。在本文中，我们提出并证明了基于光学偏振分集，可以在单个空间单元的两个子空间之间实现PT对称性。通过控制单个空间单元中光的偏振态，可以调节两个偏振环的局域本征频率、增益、损耗和耦合系数，从而导致PT对称性破缺。作为一个示例，实现了一种基于此概念的光纤环形激光器，该激光器无需使用超窄带通滤波器就能支持稳定的单模激光振荡。
