Preparation and sensing characteristics of long-period fiber gratings based on periodic microchannels
doi: 10.37188/CO.EN-2024-0005
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摘要:
长周期光纤光栅具有体积小、耐腐蚀、抗电磁干扰和灵敏度高等优点,使其广泛应用于生物医学、电力工业以及航空航天等领域。本文提出了一种基于周期微通道的长周期光纤光栅传感器。首先通过飞秒激光微加工在单模光纤的包层中刻蚀出一系直线结构,然后通过湿法腐蚀技术对激光改性区域进行选择性腐蚀以获得周期性微通道结构,最后在通道中填充聚二甲基硅氧烷(PDMS)以改善光谱质量。实验结果表明,该传感器可以进行温度、应力、折射率和弯曲等传感参数测量,具有良好的传感灵敏度。温度灵敏度为−55.19 pm/°C,应变灵敏度为−3.19 pm/με,最大折射率灵敏度为540.28 nm/RIU,弯曲灵敏度为2.65 dB/m−1,且均表现出良好的线性响应。该传感器在精密测量和传感领域有良好的应用前景。
Abstract:Long-period fiber gratings have the advantages of small size, corrosion resistance, anti-electromagnetic interference, and high sensitivity, making them widely used in biomedicine, the power industry, and aerospace. This paper proposes a long-period fiber grating sensor based on periodic microchannels. First, a series of linear structures were etched in the cladding of a single-mode fiber by femtosecond laser micromachining. Then, the laser-modified region was selectively eroded by selective chemical etching to obtain the periodic microchannel structure. Finally, the channels were filled with polydimethylsiloxane (PDMS) to improve the spectral quality. The experimental results show that the sensor has good sensitivity in the measurement of various parameters such as temperature, stress, refractive index, and bending: it has a temperature sensitivity of −55.19 pm/°C, a strain sensitivity of −3.19 pm/με, a maximum refractive index sensitivity of 540.28 nm/RIU, and a bending sensitivity of 2.65 dB/m−1. All of the measurement parameters show good linear responses. The sensor has strong application prospects in the field of precision measurement and sensing.
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Table 1. Comparison of measurement parameters for different types of LPFG
Year Sensing structure Temperature sensitivity Strain sensitivity RI sensitivity Bending sensitivity Reference 2013 Periodic microchannels 9.95 pm/°C −2.4 pm/με −391 nm/RIU − [19] 2017 Hollow ellipsoid − − − 0.42 dB/m−1 [21] 2022 Inner microholes 13.06 pm/°C −1.57 pm/με − − [20] 2022 Micro air-channel 12.1 pm/°C − 587.08 nm/RIU − [26] 2023 Taped two-mode fiber and PDMS −0.412 nm/°C −12.16 nm/MPa − − [6] 2023 D-shape 45 pm/°C − − 17.6 nm/ m−1 [27] 2024 Periodic microchannels on the
cladding and PDMS−55.19 pm/°C −3.19 pm/με 540.28 nm/RIU 2.65 dB/m−1 This work -
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