In this paper, a set of experimental equipment is outlined which is designed to eliminate temperature change influence in stress measurement. A Fiber Bragg Grating (FBG) is fixed to a specially-structured cantilever, then the load brought to beat at the free end of cantilever. As the load exerted to the cantilever is changed, the stress of FBG changes. From the experiment, we can see that at the beginning of distortion caused by the load, the center wavelength of fiber grating changes, but the chirp effect is not obvious. As the load increases, the spectrum of reflecting peak becomes wider, and
the chirp effect becomes more obvious, then two reflecting peaks appear, and the distance of two center wavelengths increases as linearity. When weights are added to 200g, two center wavelengths are 1548.25nm and 1548.43nm and the distance of them is 0.18nm. Experimental results indicate that the distance of two reflect peaks changes in linear relationship with the increasing of load on the free end of the cantilever, and the linearity is up to 0.96. Using this way to package FBG, the cross-sensitivity of stress and temperature can be conquered, and the error caused by temperature change in stress measurement can be eliminated. Therefore, the stress measurement can be realized by one fiber grating.
In this paper, a novel temperature stabilization technique for Fiber Bragg Grating is presented, named dual-arm adverse expanding technique. Experiment demonstrates, the Bragg wavelength shift of FBG treated with this technique is only 0.03nm in range from 12°C to 62°C. It is equivalent to 0.07 nm/100°C. Temperature stability of FBG treated is 14 times higher than that of bare one. The Bragg wavelength shift of FBG induced by temperature is eliminated mostly.