[FBG Self-Chirped Based on an Sine-Structure].

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 was up to 8 mm and the chirp grating reflection spectrum with multiple peaks; The transfer 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.