Dynamic signal sensing using fiber Bragg grating sensor and interferometric interrogation

Abstract

We report our recent experimental studies on phase generated carrier (PGC) based fiber Mach-Zehnder interferometer (F-MZI) interrogation technique for fiber Bragg grating (FBG) sensors. Interferometric techniques such as F-MZI have emerged as most sensitive and accurate technique for demodulation of signal generated by FBGs. F-MZIs are widely used for dynamic strain measurement applications such as vibration analysis, hydrophones, and acoustic emission studies. But, a fiber interferometer is inherently very sensitive to surrounding parameters of temperatures, pressure, and air currents which makes it unsuitable to be used directly as FBG wavelength shift demodulator. So, a PGC is incorporated in MZI to remove these influences. This paper shows the experimental results which supports PGC based demodulation scheme for dynamic signal sensing. FFT based noise elimination technique has also been used here to remove unwanted surrounding and system noises. We have also compared this PGC based F-MZI with CCD spectrometer for demodulation of dynamic signals generated by FBG sensor.