Optimization-Design of Mach-Zehnder interferometer and its application in a fiber Bragg grating phase sensor demodulation

摘要

A fiber Bragg grating phase sensor demodulation scheme is demonstrated in this paper. An unbalanced Mach-Zehnder interferometer is used as the wavelength shift detector. The sensing fiber Bragg grating is attached on a piezoelectric transducer, through which a vibration signal is applied on the grating. To improve the fringe visibility of the output spectra of the Mach-Zehnder interferometer, we investigate the characteristics with detail. We find that there is an optimum optical path difference between the two arms of the interferometer. We successfully design and produce two Mach-Zehnder interferometer whose OPD are about 2.54mm and 2.12mm, and the relevant visibility are 9.7dB, 18dB, respectively. The experimental results have some potential applications in some regions, such as strain, temperature, and vibration detection.