Cao Zhitao, Jiang Lan, Wang Sumei, Wang Mengmeng, Liu Da, Wang Peng, Zhang Fei, Lu Yongfeng
Appl Opt. 2015 Mar 20;54(9):2371-5. doi: 10.1364/AO.54.002371.
An all-glass extrinsic Fabry-Perot interferometer (EFPI) is demonstrated for thermal-optic coefficient (TOC) of water, glycerol, and their mixture (volume ratio of 1:1). The compensation for the thermal expansion of Fabry-Perot (FP) cavity is realized by assembling a glass capillary and optical fibers through a CO laser welding. The thermal responses of EFPIs are tested in air at different cavity lengths of 578.6 μm, 911.7 μm, and 1520.3 μm, respectively. The corresponding refractive index errors induced by thermal expansion of FP cavity are negligible, which are demonstrated to be 4.33×10 RIU/°C, 4.13×10 RIU/°C, and 3.45×10 RIU/°C when temperature increases from 20.03°C to 60.78°C. The thermal-optic coefficients of water, glycerol, and their mixture are measured to be -1.5×10 RIU/°C, -2.3×10 RIU/°C, and -2.0×10 RIU/°C, respectively. Our study suggests a potential use of this sensor for TOC measurements of liquids with the advantages of low costs and robustness.
展示了一种全玻璃外腔法布里-珀罗干涉仪（EFPI）用于测量水、甘油及其混合物（体积比1:1）的热光系数（TOC）。通过用CO激光焊接组装玻璃毛细管和光纤，实现了法布里-珀罗（FP）腔热膨胀的补偿。分别在空气环境中对不同腔长（578.6μm、911.7μm和1520.3μm）的EFPI进行热响应测试。FP腔热膨胀引起的相应折射率误差可忽略不计，当温度从20.03°C升高到60.78°C时，这些误差分别为4.33×10⁻⁶RIU/°C、4.13×10⁻⁶RIU/°C和3.45×10⁻⁶RIU/°C。测得水、甘油及其混合物的热光系数分别为-1.5×10⁻⁶RIU/°C、-2.3×10⁻⁶RIU/°C和-2.0×10⁻⁶RIU/°C。我们的研究表明这种传感器在液体TOC测量方面具有潜在应用，具有低成本和坚固耐用的优点。
