2019/04/15 by Arnab Laha, Harsh K. Gandhi, Laha, Arnab +9
Physics and Astronomy · #FOS: Physical sciences #Optics (physics.optics) #physics.optics
paper · pdf · doi:10.48550/arxiv.1904.06967
6 pages, 4 figures
arxiv created 2019/04/15 · arxiv updated 2019/04/16
We investigate the astonishing physical aspects of Exceptional Points (EPs) in a 1D planar few-mode optical waveguide. The waveguide hosts four quasi-guided modes. Here interactions between the selected pair of modes are modulated by a spatial distribution of inhomogeneous gain-loss profile. Both the coupled pairs approach two different second-order EPs in parameter plane. Considering a proper parametric loop to encircle the identified EPs simultaneously, we establish a specific topological feature where one round encirclement in parameter space yields the switching between the propagation constants (β) of the corresponding pairs of couple modes in complex β-plane. Choosing two different patterns of the parametric loop, we establish the immutable topology in β- switching phenomena. This robust mode conversion scheme shall provide a platform to realize selective mode switching devices or optical-mode converters.