Exceptional Point Engineering and Optical Transport in Coupled Double Waveguides

Exceptional points (EPs), as spectral singularities unique to non-Hermitian systems, have been extensively studied in PT-symmetric frameworks. This work constructs a non-PT-symmetric coupled waveguide array, successfully observes multiple EPs and reveals the rich optical phenomena they induced. Theoretical analysis demonstrates the presence of various EPs in the system’s Hamiltonian and scattering matrices, which partition the parameter space into multiple regions with distinct transmission behaviors. These EPs can excite non-Hermitian effects, including unidirectional transmission, signal amplification, periodic oscillations, and divergent responses. The diverse optical phenomena observed in this study provide new perspectives for the design and application of novel non-Hermitian photonic devices.