Cross-sensitivity of Fiber Grating Solved by FFP Triangle Notch Filter

Employing a fiber Fabry-Perot (FFP) interferometer has been considered as a triangle notch filter to demodulate the wavelength of fiber Bragg grating (FBG) sensor. The single parameter of strain has been demodulated, and the cross-sensitivity influence of temperature has been eliminated. The principle of this method is simple and easy to be implemented, and has been used to design a 30 t fiber grating weightbridge successfully. The maximal temperature drift error of the weightbridge is 4με, which means that the full scale error is 8‰. The result reveals that the accuracy is high enough to be used in measurement.