Asian Journal of Physics Vol. 34, Nos 11 & 12 (2025) 669-675

Exploring exclusive light dynamics around an exceptional point in an all-lossy dual-core photonic crystal fiber

Shamba Ghosh1, Arpan Roy2, Bishnu P Pal3 and Somnath Ghosh3
1Department of Physics, Indian Institute of Technology Jodhpur, Jodhpur-342 030, India
2Institute of Radio Physics and Electronics, University of Calcutta, Kolkata-700 009, India

3Department of Physics, École Centrale School of Engineering, Mahindra University, Hyderabad-500 043, Telangana, India

(In loving memory of Revered Professor M. S. Sodha)

We report the design and analysis of an all-lossy dual-core photonic crystal fiber (PCF) capable of hosting a second-order exceptional point (EP2) without the need for gain. The structure consists of two defect regions acting as cores, embedded within a hexagonal lattice of air holes, with the entire cladding embedded in a fixed background loss. An asymmetric imaginary refractive index distribution between the two cores is used to control modal interaction, enabling coalescence of two modes at the EP2. The existence of the exceptional point is confirmed through the coalescence of both the real and imaginary parts of the complex propagation constants. Furthermore, the branch point topology of the EP2 is validated by tracking the complex modal eigenvalues under a closed parametric loop in the gain–loss parameter space. The proposed all-lossy PCF provides a practical and fabrication-compatible route for realizing non-Hermitian topological singularities, making it a promising platform for next-generation integrated photonic devices based on exceptional point physics. © Anita Publications. All rights reserved.
Doi: XXX
Keywords: Exceptional point, non-Hermitian system, Photonic crystal fiber.

Peer Review Information
Method: Single- anonymous; Screened for Plagiarism? Yes
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