A screw-shape is fabricated on a commercial plastic optical fiber (POF) by a heat pressing and twisting method. The screw-shaped POF is proposed as a refractive index (RI) sensor. By changing the structural parameters of the screw-shaped POFs both with and without claddings, the RI sensing performances are studied. When the screw-shaped POF is fabricated by twisting a thin flat-shaped POF with a thickness of $600~\mu \text{m}$ and with a screw pitch of 2mm, the highest sensitivities of 2277%/RIU, 4318%/RIU, and 4399%/RIU with the resolutions of $3.10\times 10^{\mathbf {-4}}$ RIU, $1.63\times 10^{\mathbf {-4}}$ RIU, and $1.60\times 10^{\mathbf {-4}}$ RIU are obtained in the RI ranges of 1.33-1.37, 1.37-1.40, and 1.41-1.45, respectively. The results demonstrate that simply making the POF into a screw-shape, its RI sensing performance can be enhanced markedly. As a low-cost solution for RI measurement, the proposed sensor has the merits of high sensitivity, simple structure, easy fabrication, and intensity modulation at visible wavelengths.

中文翻译：

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用于折射率传感的螺旋形塑料光纤

通过热压和扭曲方法在商用塑料光纤 (POF) 上制造螺旋形状。螺旋形 POF 被提议作为折射率 (RI) 传感器。通过改变带包层和不带包层的螺旋形 POF 的结构参数，研究了 RI 传感性能。当螺旋形 POF 是通过扭转厚度为 $600~\mu \text{m}$ 螺距为2mm，最高灵敏度为2277%/RIU、4318%/RIU、4399%/RIU，分辨率为 $3.10\times 10^{\mathbf {-4}}$ 里乌， $1.63\times 10^{\mathbf {-4}}$ RIU，和 $1.60\times 10^{\mathbf {-4}}$ RIU 分别在 1.33-1.37、1.37-1.40 和 1.41-1.45 的 RI 范围内获得。结果表明，简单地将 POF 制成螺旋形，其 RI 传感性能可以显着提高。作为一种低成本的 RI 测量解决方案，所提出的传感器具有灵敏度高、结构简单、易于制造和可见光波长下的强度调制等优点。