Refractive Index and Temperature Sensing Using Inter-Core Crosstalk in Multicore Fibers
Refractive Index and Temperature Sensing Using Inter-Core Crosstalk in Multicore Fibers
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DOI：
10.1109/jlt.2019.2917629
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发表时间：
2019-09-15
影响因子：
4.7
通讯作者：
Sales, Salvador
中科院分区：
文献类型：
--
作者：
Madrigal, Javier;Barrera, David;Sales, Salvador
多芯光纤是光学传感领域的研究热点。它们的核心多样性和空间分布使传感机制的发展成为可能，这是单芯光纤不可能实现的。在本文中，我们研究了利用芯间串扰现象来实现周围折射率(SRI)传感器。倾斜光纤布拉格光栅(TFBG)的选择性刻写故意增加了刻录的纤芯之间的串扰，使其对SRI敏感。与分析单芯光纤中TFBG的透射谱相比，该技术简化了SRI的测量，提高了对激励包层模式的识别和跟踪。所提出的装置对温度也很敏感。温度由串扰波长漂移得到，测量灵敏度为9.75 pm/℃。SRI由串扰光功率测量得到。随着SRI的增加，包层模式逐渐衰落，降低了串扰光功率。我们观察到倾斜度越高，传感器的灵敏度就越高。对于7度TFBG，从1.31到1.39，SRI灵敏度为-74.2dB/RIU；从1.39到1.44，SRI灵敏度为-250.8 dB/RIU。
Multicore optical fibers are of great interest in the optical sensing field. Their core diversity and spatial distribution enable the development of sensing mechanisms that are not possible in single-core fibers. In this paper, we study the use of the inter-core crosstalk phenomena for the implementation of a surrounding refractive index (SRI) sensor. The selective inscription of a tilted fiber Bragg grating (TFBG) intentionally increases the inter-core crosstalk between the inscribed cores and makes it sensitive to the SRI. With this technique we simplify the measurement of the SRI and improve the identification and tracking of the excited cladding modes, as compared with the analysis of the transmission spectrum of a TFBG in single-core fibers. The proposed device is also sensitive to temperature. Temperature is obtained from the crosstalk wavelength shift with a measured sensitivity of 9.75 pm/degrees C. The SRI is obtained from the measurement of the crosstalk optical power. For increasing SRIs the cladding modes gradually fade, reducing the crosstalk optical power. We observed that the higher the tilt, the higher the sensor sensitivity. For a 7 degrees TFBG the SRI sensitivity obtained is -74.2 dB/RIU from 1.31 to 1.39 and -250.8 dB/RIU from 1.39 to 1.44.