| Because of the inimitable advantages, brillouin fiber-optic sensing technology gets more and more attention and gradually be applied in practice. In this paper, the dependences of brillouin shift and intensity on temperature and strain are investigated theoretically. A brillouin distributed sensing system for simultaneous temperature and strain measurement based on heterodyne detection is proposed. Characteristics of brillouin scattering signal are studied. The relationship between the signal instantaneous phase and frequency is simulated and analysed. The algorithm of instantaneous frequency detection was presented. The high precision will be obtained with high SNR. Simulation results show that data fitting method can improve the real-time characteristic. |
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