In this study, a refractive-index guiding single-crystal fiber (SCF) with air–solid cladding was proposed and numerical simulation investigation was carried out. In general, refractive-index guided cladding was constructed through air-holes in the solid material. It resulted in the effective reduction in the number of guided-modes, and the single-mode and few-mode transmission could be realized. The influences of different materials with different refractive indices, cladding structure, and fabrication errors on the confinement loss and effective guided-mode number with the variation in wavelength from 2.5 to 3.2 µm were numerically investigated by the finite element method. Thus, the optimal design of the SCF was successfully obtained. This study may open a new avenue for the design of SCFs and their applications in the fiber lasers and sensors.

中文翻译：

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具有空气-固体包层的折射率引导单晶光纤

在这项研究中，提出了一种具有空气-固体包层的折射率引导单晶光纤 (SCF)，并进行了数值模拟研究。通常，折射率引导包层是通过固体材料中的气孔构建的。有效减少了导模数，实现了单模和少模传输。通过有限元方法数值研究了具有不同折射率、包层结构和制造误差的不同材料对限制损耗和有效导模数随着波长从 2.5 到 3.2 µm 变化的影响。因此，成功地获得了 SCF 的优化设计。这项研究可能为 SCF 的设计及其在光纤激光器和传感器中的应用开辟一条新途径。