根据长周期光纤光栅具有多个不同损耗峰的光谱特性提出了一种使用单个LPG对温度和应变两参数进行同时区分测量的新方案。 实验选用了具有不同温度和应变传感灵敏度的第一和第四损耗峰, 通过观测其相应的光谱图, 得到因测量参数变化而导致的谐振波长的偏移。 根据相应的参数求解矩阵方程, 当被测量变化较小时, 通过计算可知, 交叉敏感对参数的测量基本上不产生影响； 而当被测量变化较大时, 可通过适当补偿消除交叉敏感而带来的偏差。 实验测得的温度和应变误差分别是±0.92 ℃和±22 με, 该方案能较好地解决测量中存在的应变和温度之间的交叉敏感问题, 有效地提高了系统的测量精度。 实验结果表明,利用长周期光纤光栅的不同损耗峰同时测量温度和应变的方法是切实可行的, 且实验系统体积小, 成本较低, 简单实用, 具有较好的应用前景。on a Long Period Grating’s Spectrum

The new scheme of using a long period grating for simultaneousdiscriminating measurement of temperature and strain is proposed. The scheme isbased on the long period grating’s spectrum characteristics. The spectrum iscomposed of multiple and different loss peak. The resonant wavelength of thefirst and fourth-order loss peak with different temperature and strainsensitivity was selected in this experiment. The wavelength shift resulting fromparameter variation can be obtained by observing its corresponding spectrum. Thetemperature was acquired by a study on the temperature characteristic of a LPG.The strain sensitivity was obtained by the research on the strain characteristicof a LPG. The standard matrix equation was set up and solved according to thecorresponding parameter. The authors know by calculating the standard matrixequation that the cross-sensitivity has little influence on the measurement ofthe parameter. As the effect of cross-sensitivity is lower than the resolution ofthe LPG in this case, we can eliminate the deviation due to the cross-sensitiveby appropriate compensation. The errors of temperature and strain were calculatedto be ±0.92 ℃ and ±22 με respectively. The cross-sensitivity betweentemperature and strain was decreased and the measuring precision of the systemwas improved by using this scheme in which a single long period grating was usedto test two measurands. By comparison between the applied and the calculatedtemperature and strain of a LPG, the experiment results showed that the methodsare feasible.The experimental system is small and the cost is relatively low. Theexperimental device is simple and practical and has good application prospect.Simultaneous measurement; FiberBK2009370), 航空科学基金项目(2008ZD52047)和南京航空航天大学研究生创新基地(实验室)开放基金项目(200901001)资助