基于拉伸装置的光纤应变系数标定及误差分析

Calibration and Error Analysis of Strain Coefficient of Optical Fiber Based on Stretching Device

在分布式光纤传感系统中,由于生产厂家、材料、掺杂及生产工艺等的不同,传感光纤的折射率、应变系数及温度系数等基本参量各有差异,在投入使用前必须对其进行标定。提出了基于拉伸装置标定光纤应变系数的方法并系统地进行了误差分析。采用G.652单模光纤,针对不同初始长度进行了多次标定实验,标定的应变系数在0.050 2～0.051 2(MHz/με)之间,重复性好。通过BOTDR验证,实测应变值与理论计算结果吻合的得较好。实验结果表明:该标定方法切实可行、易于实现,既可用于对光纤传感系统的标定,也能用于BOTDR在生产过程中的应变校准。

In the distributed optical fiber sensor system, due to the difference of the manufacturer, materials, doping and the production process etc., the basic parameters of optical fiber sensor such as the refractive index, strain and temperature coefficient are slightly different, and it must be calibrated for sensing fiber before application. A method for calibrating the strain coefficient of optical fiber based on Brillouin Optical Time Domain Reflectometer （BOTDR） and stretching device was proposed, then the error analysis was presented. Several calibration experiments were conducted on G.652 single mode fiber with different initial length, and the strain coefficients calibrated were 0.050 2 ~ 0.051 2 （MHz/με）, which showed good repeatability. Verified by BOTDR, the measured strain values agreed well with the results of theoretical calculation. The experimental results show that the calibration method is practical, easy to be implemented. It can be used both for the calibration of optical fiber sensing system and for the strain calibration of BOTDR in the production process.