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Parity-time-symmetric (PT-symmetric) optical waveguide couplers offer a great potential for future applications in integrated optics, such as ultracompact reconfigurable all-optical signal processing. Here, we predict a nonlinearly triggered transition from a full to a broken PT-symmetric regime in finite-size systems described by smooth permittivity profiles and, in particular, in a conventional discrete waveguide directional coupler configuration with a rectangular profile. For these systems, we show that this phase transition occurs in PT-symmetric couplers, regardless of the details of their geometry, therefore suggesting a practical route for experimental realization of such systems.
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http://dx.doi.org/10.1364/OL.40.005327 | DOI Listing |
Microsyst Nanoeng
May 2025
Key Laboratory of MEMS of the Ministry of Education, Southeast University, Nanjing, 210096, China.
Parity-time (PT) symmetric resonators have an exact phase with real frequency eigenvalues and a broken phase with complex-conjugate frequency eigenvalues. In the presence of nonlinear gain, the PT-symmetric resonator exhibits nonreciprocal transmission when it is biased at the broken phase, which promises applications for isolators and circulators in modern communication systems. The nonlinear distortion performance is one of the most important metrics in most electronic applications where linearity is critical.
View Article and Find Full Text PDFThis paper demonstrates solitons in the nonlinear media with parity-time (PT) symmetric sawtooth lattices. These PT lattices exhibit several uncommon features, of which the most striking are the flat Bloch bands, in which the local modes are stable and the depths of imaginary parts are large when the PT symmetry breaks up. Furthermore, we investigate the formation, properties, and dynamics of fundamental, multipole, and two kinds of vortex-carrying solitons that all reside in the semi-infinite bandgaps of the underlying linear Bloch wave spectrum.
View Article and Find Full Text PDFNat Commun
October 2024
Key Laboratory of MEMS of the Ministry of Education, Southeast University, Nanjing, China.
An inductor-capacitor passive wireless sensor is essential to physical, chemical, and biological sensing for scenarios where physical access is difficult. Exceptional points of parity-time symmetric inductor-capacitor systems featuring the linear loss and gain have been utilized for enhancing sensing. However, the exceptional point sensing scheme might bring about fundamental resolution limits and noise enhancement.
View Article and Find Full Text PDFChaos
July 2024
Department of Physics, Farook College Calicut, University of Calicut, Kozhikode, Kerala 673632, India.
PLoS One
December 2023
College of Science, China Agricultural University, Beijing, China.
We study the nonlinear localized modes in two-component Bose-Einstein condensates with parity-time-symmetric Scarf-II potential, which can be described by the coupled Gross-Pitaevskii equations. Firstly, we investigate the linear stability of the nonlinear modes in the focusing and defocusing cases, and get the stable and unstable domains of nonlinear localized modes. Then we validate the results by evolving them with 5% perturbations as an initial condition.
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