We propose two mid-infrared photonic crystal fibers with an elliptical As₂S₃ core and a dual-cladding structure with high birefringence and high nonlinearity. The cladding filling material is silica and the core material is As₂S₃. The full vector finite-element method is used to study the birefringence, and nonlinear coefficient of the structure in the 3–5 μm band. The Simulation results show that the birefringence of the two structures can reach a maximum of 0.2169, and the nonlinear coefficient can reach a maximum of 3763.42 W⁻¹/km. From these characteristics, it is concluded that the proposed structure will be ideal for mid-infrared fiber sensing, precision optics and nonlinear optics.

中文翻译：

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高双折射，高非线性的中红外双包层光子晶体光纤

我们提出了两条椭圆形的As ₂ S ₃核和具有高双折射和高非线性的双包层结构的中红外光子晶体光纤。包层填充材料为二氧化硅，芯材为As ₂ S ₃。使用全矢量有限元方法研究结构在3–5μm波段的双折射和非线性系数。仿真结果表明，两种结构的双折射最大可达到0.2169，非线性系数最大可达到3763.42 W ^-1 / km。从这些特性可以得出结论，所提出的结构对于中红外光纤传感，精密光学和非线性光学将是理想的。