基于色散效应的光纤光栅高速高精度解调方法研究  

High speed and high precision demodulation method of fiber grating based on dispersion effect

作　　者：李政颖[1,2] 周磊[1] 孙文丰[1] 李子墨 王加琪 郭会勇[2] 王洪海[2] Li Zheng-Ying Zhou Lei Sun Wen-Feng Li Zi-Mo Wang Jia-Qi Guo Hui-Yong Wang Hong-Hai(Key Laboratory of Optical Fiber Sensing Technology and Information Processing, Ministry of Education, Wuhan University of Technology, Wuhan 430070, China National Engineering Laboratory for Fiber Optic Sensing Technology, Wuhan University of Technology, Wuhan 430070, China)

机构地区：[1]武汉理工大学,光纤传感技术与信息处理教育部重点实验室,武汉430070 [2]武汉理工大学,光纤传感技术国家工程实验室,武汉430070

出　　处：《物理学报》2017年第1期112-120,共9页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:61575149)资助的课题

摘　　要：利用普通单模光纤(SMF)与色散补偿光纤(DCF)分别具有正色散和负色散系数特性,实现光纤光栅阵列的高速高精度解调.系统采用全光纤结构,仅需发出单一高速光脉冲,即可根据反射光脉冲时延差同时获取各个光栅的波长与位置信息,大幅提高了光纤光栅解调速度;通过建立DCF-SMF双通道和色散差矫正模型,削弱了温度变化及色散值误差对系统解调精度的影响.实验表明,本方法解调速率可达1 MHz,解调过程受传感网络光纤及双通道温变影响较小,具有良好稳定性及高精度;5—75?C温度扰动实验中,传感网络传输光纤温变时系统解调均方差16.8 pm,DCF-SMF双通道受温度扰动时系统解调均方差为11.9 pm,恒温下系统长时间解调时均方差为6.4 pm;应力实验中,解调线性度可达0.9998,解调精度约为8.5 pm.Fiber Bragg grating sensor is widely used in military, construction, transportation, aviation and other fields due to its advantages in high sensitivity, high precision, high multiplexing and small volume. However, in some special fields such as ultrasonic flaw detection, high-speed vibration and aeroengine monitoring, the signals are rapidly changing, thus requiring high speed sampling. But the demodulation speed of traditional fiber Bragg grating demodulation techniques is hardly to satisfy the requirements, which seriously limits the application of fiber Bragg grating sensor in these fields.To solve this problem, in this paper we propose a dispersion compensation fiber（DCF）-single mode fiber（SMF） dualchannel demodulation method. Based on the SMF and the DCF with the characteristics of positive and negative dispersion coefficients in the anomalous dispersion region respectively, and combining with the optical time domain reflection technology, high speed and high precision demodulation of fiber grating can be realized. This system adopts the whole fiber structure without wavelength scanning, and the grating wavelength and position information can be obtained according to the pulse delay difference under a single optical pulse. There are three factors that quite influence the system accuracy and need to be solved： the grating space disturbance which is caused by the temperature change of the sensor network fiber; the dual-channel length disturbance caused by the DCF-SMF dual-channel temperature change;the dispersion disturbance caused by the inaccurate dispersion difference of the DCF-SMF. By constructing the DCF-SMF dual-channel, adopting the reference grating and introducing the dispersion difference correction model, these influence factors are solved. The case of temperature disturbance elimination is tested by the 5–75？C temperature experiments.And the results are as follows： when the temperature of the sensor network fiber changes, the standard deviation of this dual-channel demodulation sy

关 键 词：光纤传感 普通单模光纤 色散补偿光纤 高速高精度 

分 类 号：TN253[电子电信—物理电子学]