正弦形构造的光纤光栅自致啁啾效应

FBG Self-Chirped Based on an Sine-Structure

结合均匀光栅在受到非均匀应变时会产生啁啾效应的原理,提出了一种利用正弦结构将均匀光栅调制成啁啾光栅的方法。设计了正弦结构的基底材料,将光纤光栅粘贴在基底材料的应变非均匀区,通过施加拉伸载荷将其产生的应变引入FBG栅区,使得FBG产生了啁啾效应,FBG被调制成具有多个反射峰和宽带宽的啁啾光栅;使用有限元软件对正弦结构拉伸载荷下的应变进行了仿真,得到了正弦结构不同位置的应变云图;实验结果在位移载荷最大为8mm时,得到了带宽增加5倍,反射谱具有多个反射峰的啁啾光栅;结合传输矩阵法对啁啾光栅的反射谱进行光谱仿真重构,仿真光谱与实验光谱趋势基本吻合。

Considerting that the uniform grating can be induced chirp effect under non-uniform strain,a method of making chirp grating by uniform grating with the use of sine structure is proposed.The sine structure was designed as basal material while the fiber Bragg and grating was pasted in the strain non-uniform area of basal material.the strain it produced was introducied into FBG gate area by applying tensile load to achieve FBG produce chirp effect.FBG was made with multiple peaks and wide bandwidth of the chirp grating.The finite element software was used to simulate the strain of sine-structure under tensile loading to get strain contours of the sinusoidal structure in different positions;The experimental results showd that the bandwidth has been increased five times when the displacement load wasup to 8mm and the chirp grating reflection spectrum with multiple peaks;Thetransfer matrix method to reflection spectrum of chirp grating was combined for spectrum simulation reconstruction and the simulation spectrum spectrum trend was consistent with the experimental results.The chirp grating made in this method has an important application in complex strain field multiple parameters and achieving sense of temperature without compensation by the use of the bandwidth of the chirp grating at the same time.