Demodulation scheme for filtering method based fiber Bragg grating sensing

Because the sensitivity of the fiber Bragg grating (FBG) sensor to the strain and temperature is observed through the variation of its reflected light wavelength, it is important for FBG sensor to measure the change of the wavelength. Although there are many demodulation methods nowadays, filtering demodulation technique finds more applications because the measurement devices are easy to make, simple in structure and convenient to operate. Eight kinds of filter based demodulation methods are introduced in order to select an optimum demodulation method for the specific application, these demodulations are compared in terms of cost, accuracy, measurement range, manufacture of the devices and applicable environment, their advantages and disadvantages are analyzed. The optical wavelet transform filtering is introduced emphatically, the principle of the measurement system is discussed in depth and its potential applications are pointed out.