Long Period Gratings in Multicore Optical Fibers for Directional Curvature Sensor Implementation
Long Period Gratings in Multicore Optical Fibers for Directional Curvature Sensor Implementation
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DOI：
10.1109/jlt.2017.2764951
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发表时间：
2018-02-15
影响因子：
4.7
通讯作者：
Sales, Salvador
中科院分区：
文献类型：
--
作者：
Barrera, David;Madrigal, Javier;Sales, Salvador
由于不同纤芯的空间分布，多芯光纤对于曲率和形状传感器的制造特别有吸引力。光纤布拉格光栅在过去已经被用于这些传感器的实现，然而，尽管它们的固有特性，它们具有非常有限的灵敏度。在本文中，我们研究了使用长周期光栅（LPGs）的方向性曲率传感器的实现。我们刻在一组三个不同的LPG在七芯光纤使用选择性的铭文技术。我们在外核中刻上了一个LPG，在中央核中刻上了三个LPG的阵列。我们的特点是所提出的传感器的应变，扭转和曲率的大小和方向。该传感器对0 ~ 1.77 m（-1）的曲率幅值具有线性响应，最大曲率灵敏度为-4.85 nm/m（-1），在0 ~ 360 °的曲率方向上，所有纤芯均表现出近似正弦的特性。该传感器显示出良好的应变不敏感性。利用外纤芯中LPG的最大衰减，可以检测和测量多芯光纤中的扭转。
Multicore optical fibers are especially attractive for the fabrication of curvature and shape sensors due to the spatial distribution of the different cores. Fiber Bragg gratings have been used in the past for the implementation of these sensors, however, despite their inherent properties, they have a very limited sensitivity. In this paper, we study the use of long period gratings (LPGs) for the implementation of a directional curvature sensor. We inscribed a set of three different LPGs in a seven core optical fiber using a selective inscription technique. We inscribed a single LPG in the external cores and an array of three LPGs in the central core. We have characterized the proposed sensor for strain, torsion, and curvature magnitude and direction. The proposed sensor shows a linear response for curvature magnitudes from 0 to 1.77 m(-1) with a maximum curvature sensitivity of -4.85 nm/m(-1) and shows a near sinusoidal behavior in all the cores with curvature directions from 0 degrees to 360 degrees. The sensor shows a good insensitivity to strain. The torsion in the multicore optical fibers can be detected and measured using the maximum attenuation of the LPGs in the external cores.