Zaghloul Mohamed A S, Wang Mohan, Milione Giovanni, Li Ming-Jun, Li Shenping, Huang Yue-Kai, Wang Ting, Chen Kevin P
Department of Electrical and Computer Engineering, University of Pittsburgh, Pittsburgh, PA 15261, USA.
Optical Networking and Sensing Department, NEC Laboratories America, Inc., Princeton, NJ 08540, USA.
Sensors (Basel). 2018 Apr 12;18(4):1176. doi: 10.3390/s18041176.
Brillouin optical time domain analysis is the sensing of temperature and strain changes along an optical fiber by measuring the frequency shift changes of Brillouin backscattering. Because frequency shift changes are a linear combination of temperature and strain changes, their discrimination is a challenge. Here, a multicore optical fiber that has two cores is fabricated. The differences between the cores' temperature and strain coefficients are such that temperature (strain) changes can be discriminated with error amplification factors of 4.57 °C/MHz (69.11 μ ϵ /MHz), which is 2.63 (3.67) times lower than previously demonstrated. As proof of principle, using the multicore optical fiber and a commercial Brillouin optical time domain analyzer, the temperature (strain) changes of a thermally expanding metal cylinder are discriminated with an error of 0.24% (3.7%).
布里渊光时域分析是通过测量布里渊背向散射的频移变化来感知沿光纤的温度和应变变化。由于频移变化是温度和应变变化的线性组合，因此区分它们是一项挑战。在此，制造了一种具有两个纤芯的多芯光纤。纤芯的温度和应变系数之间的差异使得温度（应变）变化能够以4.57℃/MHz（69.11με/MHz）的误差放大因子被区分，这比之前所展示的低2.63（3.67）倍。作为原理验证，使用该多芯光纤和一台商用布里渊光时域分析仪，对一个热膨胀金属圆柱体的温度（应变）变化进行区分，误差为0.24%（3.7%）。
