FBG测温系统的光谱校正算法的研究

为了解决在大范围、多点位温度实时监测过程中温度传感器铺设工程复杂、维护成本高等问题，研究开发了基于光纤布拉格光栅结构的温度监测系统。利用光纤光栅衍射对波长的选择性，建立了温度与波长的函数关系，通过计算波长变化量反演被测位置的温度信息。由于环境、材料等因素，光谱分布与温度变化并不满足线性变化，所以设计了光谱校正算法完成波长与温度函数的曲线拟合，曲线拟合度大于99.7%。实验采用FB136L-IAC型防爆干燥箱、LPT-200型二极管，1 550 nm光纤等对20～280 ℃范围内温度进行多点位实时检测，实验结果显示，当防爆干燥箱中的温度每改变1 ℃时，对应的中心波长向长波方向偏移大约0.04 nm，与标准温度测试数据进行对比，误差低于±0.3 ℃。由于系统采用光纤传感网络，所以具有很强的抗电磁干扰能力，而光纤光栅衍射可实现精密测量，动态响应范围大、精度高。系统的新颖之处在保证高精度测量的同时，仍满足大范围、多点位、高抗干扰能力的快速铺设，具有很强的实际应用价值。

Research on Spectrum Correction Algorithm of Temperature Measurement System Based on FBG

In order to solve the problem that temperature sensor laying is complex and maintenance cost is high in the large-scale, multi-point real-time temperature monitoring process, the temperature monitoring system based on Fiber Bragg Grating was designed and developed. Using wavelength selectivity by optical fiber diffraction grating,a function of temperature and wavelength was established. Temperature of the measured position was inversed by calculating the wavelength variation through the optical fiber Bragg grating. Due to environmental, materials and other factors, the spectral distribution and temperature changes do not satisfy linear relationship. Therefore, designed the spectrum correction algorithm was designed, and function curve fitting of wavelength and temperature was completed with a degree of fitting greater than 99.7%. Experiments used FB136L-IAC-proof oven, LPT-200 diode, and 1 550 nm optical fiber to detect 20 to 280 ℃ temperature range of multi-point in real-time. The results show that when the temperature is changed by 1 ℃, the corresponding center wavelength shifts about 0.04 nm to longer wavelengths. Compared with the test data from standard device, the error is less than ±0.3 ℃. Meanwhile, the spectral correction algorithm was applied to the system to further improve the uniformity and accuracy of the temperature detection. Because the system uses fiber-optic sensor network, it has a strong anti-electromagnetic interference capability. The diffraction grating can achieve precise measurements, so it has big dynamic range and high accuracy. The innovation of the system is to ensure high-precision measurements, while still satisfy large-scale, multi-point, high anti-jamming capability of rapid laying, and has a strong practical value.