光纤Bragg光栅应变测量中啁啾特性的研究

用光纤Bragg光栅进行应变（静态、动态）测量时，由于光栅轴向各部分受到的应变不同，因而产生布喇格中心波长漂移量发生变化.实际测量中往往忽略此扰动对光纤光栅反射谱中心波长的影响，则必然带来测量误差.采用耦合模理论，分析并研究了Bragg光栅受轴向线性应变、高次应变和非线性周期应变波等情况下的啁啾特性.根据各自啁啾特性的不同，给出了对光纤光栅反射谱中心的影响，以及测量各种应变时的测量条件和范围.

Study on the Chirp Characteristic in Strain measurement by Fiber Bragg Grating

Due to different strain of different components along the grating axis when Bragg grating is employed to measure strain (statically,dynamically),central FBG wavelength shift changes accordingly.However effect of this strain difference on central wavelength shift of fiber Bragg grating is often ignored in practical application.With coupled mode theory,as well as grating segment and transfer matrix method, chirp characterizations of fiber Bragg grating are studied when axial linear and high-order strain,non-linear periodic strain-wave are applied.Based on different chirp characterizations,measurement condition and measurement range under various kinds of strain are determined.