An open-cavity Fabry-Perot interferometer with PVA coating for simultaneous measurement of relative humidity and temperature

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• 作者：Shengnan Wu^aAuthor Vitae ; Guofeng Yan^a ; ^{yanguofeng@zju.edu.cn" class="auth_mail" title="E-mail the corresponding author}Author Vitae ; Zhenggang Lian^bAuthor Vitae ; Xiang Chen^bAuthor Vitae ; Bin Zhou^cAuthor Vitae ; Sailing He^a ; ^dAuthor Vitae
• 关键词：Fiber optics sensors ; Fabry-Perot interferometer ; PVA coating ; Humidity and temperature measurements
• 刊名：Sensors & Actuators: B. Chemical
• 出版年：2016
• 出版时间：31 March 2016
• 年：2016
• 卷：225
• 期：Complete
• 页码：50-56
• 全文大小：1693 K

文摘

A fiber-optic open-cavity Fabry-Perot (FP) interferometer (FPI) with polyvinyl alcohol (PVA) coating is proposed and experimentally demonstrated for simultaneous measurement of relative humidity (RH) and temperature. The FPI consists of an etched side-hole fiber (SHF) sandwiched in between two leading single-mode-fibers. The PVA film is plated on the fiber surface functioning as a humidity-to-refractive index (RI) transducer. Theoretical analysis details the RH and temperature influence on the spectral fringes of the FPI. Experimental results confirms and show that, the reflection loss of the FPI nonlinearly decreases more than 15 dB when the RH increases from 30%RH to 90%RH with a highest sensitivity of −1.2 dB/%RH, while the dip wavelength of the spectral fringe exhibits linear RH and temperature sensitivities of −23.1 pm/%RH and −6.14 pm/°C, respectively. Thus, by monitoring the reflection and wavelength of the interference dip, the proposed sensor enables accurate simultaneous measurement of RH and temperature. A fast and reversible time response has also been demonstrated. Such excellent sensing performance with compactness, ease of fabrication makes our sensing structure a highly promising candidate for RH and temperature monitoring applications.