基于扫频光源的光纤光栅温度和轴向拉力传感系统

Optical Fiber Grating Temperature and Axial Tension Sensing System Based on Swept Source

传统宽带光源光纤光栅(FBG)传感系统的解调部分比较复杂,为了克服这一缺点,使用线性扫频激光器作为FBG传感系统的光源,并选定一个光栅作为参考光栅,将其他光栅作为传感光栅。根据传感光栅与参考光栅的反射信号时间间隔的变化,解调得到FBG反射中心波长的变化,解调过程非常简便。基于FBG传感系统进行了温度和光纤轴向拉力的测量实验,验证了该系统的可行性和正确性,也证明了该系统可单独或同时测量温度和光纤轴向拉力。给出了提高系统测量精度的途径,包括保证参考光栅的温度稳定以及使用扫频速率较小的扫频光源和采样速率较高的示波器。

The demodulation part of a traditional fiber grating sensing system with a broadband light source is complex. In order to overcome this shortcoming, a linear swept laser is used as light source of the FBG sensor system. One of the gratings is used as reference grating, and other gratings are used as sensing gratings. The change of the reflection center wavelength of FBG is obtained according to the change of time interval between reflection signals of the sensing grating and the reference grating. The demodulation process is very simple and straightforward. The FBG sensing system is used to accomplish experiments of temperature measurement and fiber axial tension measurement. The results verify the feasibility and the correctness of the FBG sensing system and also prove that the FBG sensing system can either individually or simultaneously measure temperature and fiber axial tension. Some methods which improve the measurement precision are presented, including keeping the temperature of reference grating stable and using the swept light source with low swept rate and the oscilloscope with high sampling rate.