Distributed Fiber-Optic Vibration and Temperature Sensing System

We propose a distributed fiber-optic vibration and temperature sensing system. The proposed system can obtain coupled light of two wavelengths on one sensing arm based on the structure of the dual Mach-Zehnder interferometer by employing the wavelength division multiplexing technique. The implement scheme can achieve the parallel detection of distributed fiber-optic vibration sensing based on laser interference and distributed temperature sensing based on Raman backscattering, thus the simultaneous detection of vibration and temperature is realized. The method effectively uses the sensing fiber-optic based on the dual Mach-Zehnder interferometer and realizes simultaneous detection of vibration and temperature at a distance of 10 km in the experiment. The positioning error of vibration sensing is +/- 30 m. The spatial resolution and temperature error of temperature sensing are 1 m and +/- 1.8 degrees C, respectively. The advantage of the system is to combine laser interference with Raman backscattering effectively and realize simultaneous detection of vibration and temperature under the complicated condition. In addition, the proposed system effectively uses sensing fiber-optic and has great practical and economic value.