具有温度补偿功能的光纤光栅传感解调系统

A Novel Fiberg Grating Sensing and Demodulating System with Temperature Compensation

从理论和实验上研究了三角形光纤布拉格光栅的温度特性,结果表明:三角形光纤布拉格光栅谐振波长的温度变化率与普通光纤光栅的相同,并且其光谱形状不随温度的变化而改变。利用三角形光纤光栅光谱的这一温度特性,设计了一种具有温度补偿功能的应变传感解调系统。该系统利用斜线光纤光栅将光纤光栅应变传感的波长编码信息转换为强度,并且用信号强度与参考光强度的比值作为应变的度量值。研究表明,应变与应变度量值成线性关系,同时系统具有温度补偿功能。在三种不同的温度条件下,对悬臂梁的应变测试结果显示:在实验测量范围内,温度变化1 ℃导致的应变测量误差小于6微应变。由于采用信号强度和参考光强度的比值作为应变的度量值,避免了宽带光源的平坦度及波动对测量结果的影响。

The temperature characteristics of triangular fiber Bragg gratings have been studied theoretically and experimentally. The results show that the rate of resonant wavelength with temperature of the triangular fiber Bragg gratings is the same as that of ordinary fiber Bragg gratings, and the spectral shape of the grating can be kept without being affected by temperature. For the characteristics, a novel strain sensing and demodulating system with temperature compensation is designed. In the system, the wavelength code of strain is converted into the signal intensity, and the ratio of the signal intensity and the referent light intensity is used as the measuring value of strain. Theoretical and experimental researches indicate that the strain is proportional to the measurement value, and the system has the temperature compensation property. At three different temperature conditions, the strain test results of the cantilever experiments show that the measurement error of strain is less than 6 micro-strain /℃. For adopting the ratio of the signal intensity and the referent light intensity as the measuring value of strain, it avoids the effect to the test results coming from the flatness and fluctuating of the broad band light source.