Design of octagonal chalcogenide photonic crystal fibers: synergistic enhancement of high birefringence and high nonlinearity

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发表日期：

2026年7月17日

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Xiangqi Zheng,
Bo Wen

摘要

Photonic crystal fibers (PCFs), owing to their flexible structural design and excellent optical-control characteristics, have significant application value in the precise optical system that requires strict polarization characteristics and the scene that needs to strengthen the interaction between strong light and medium. In this study, we propose a novel octagonal PCF structure featuring asymmetric elliptical air holes in the core region, arranged in a rhombic configuration. By employing the full-vector finite-element method (FV-FEM) implemented within multiphysics simulation software, we numerically investigate the optical properties of an octagonal chalcogenide PCF, including birefringence, confinement loss (CL), and the nonlinear coefficient. Numerical results indicate that, with optimized air hole distribution, a high birefringence value of 0.2916 can be achieved at the wavelength of 1.55 µm. Furthermore, the CL for x- and y-polarized modes are reduced to 1.39 $\times $ $\times$ 10⁻⁵ dB/m and 1.88 $\times $ $\times$ 10⁻⁹ dB/m, respectively, while the nonlinear coefficients reach 3.59 $\times $ $\times$ 10⁵ W⁻¹ km⁻¹ and 3.07 $\times $ $\times$ 10⁵ W⁻¹ km⁻¹. These findings offer valuable insights for polarization control technologies and the optimal design of nonlinear optical devices.