High-Speed Mach-Zehnder-OTDR Distributed Optical Fiber Vibration Sensor Using Medium-Coherence Laser
- 98 Downloads
This article presents a high-speed distributed vibration sensing based on Mach-Zehnder-OTDR (optical time-domain reflectometry). Ultra-weak fiber Bragg gratings (UWFBG), whose backward light intensity is 2-4 orders of magnitude higher than that of Rayleigh scattering, are used as the reflection markers. A medium-coherence laser can substitute conventional narrow bandwidth source to achieve an excellent performance of distributed vibration sensing since our unbalanced interferometer matches the interval of UWFBGs. The 3 m of spatial resolution of coherent detection and multiple simultaneous vibration sources locating can be realized based on OTDR. The enhanced signal to noise ratio (SNR) enables fast detection of distributed vibration without averaging. The fastest vibration of 25 kHz and the slowest vibration of 10 Hz can be detected with our system successfully, and the linearity is 0.9896 with a maximum deviation of 3.46 nƐ.
KeywordsHigh-speed Mach-Zehnder-OTDR ultra-weak fiber Bragg grating array medium-coherence laser optical fiber vibration sensing
This work was supported in part by the National Natural Science Foundation of China (Grant No. 61735031), Natural Science Foundation of Hubei Province of China (Grant No. 2018CFA056), and the Excellent Dissertation Cultivation Funds of Wuhan University of Technology (Grant No. 2017-YS-057).
- Z. Y. Li, Z. Q. Xu, Z. H. Tang, M. Zhao, L. J. Cai, and Q. Liu, “Research of high-speed FBG demodulation system for distributed dynamic monitoring of mechanical equipment,” Advances in Mechanical Engineering, 2013, 7: 679–681.Google Scholar
- A. Gunday and S. E. Karlik, “Optical fiber distributed sensing of temperature, thermal strain and thermo-mechanical force formations on OPGW cables under wind effects,” in Proceeding of International Conference on Electrical and Electronics Engineering, Bursa, Turkey, 2013: 14–15.Google Scholar
- C. X. Zhang, Q. Li, S. Liang, W. T. Lin, L. J. Li, and X. Zhang, “Location algorithm for multi-disturbances in fiber-optic distributed disturbance sensor using a Mach-Zehnder interferometer,” in Proceeding of the 9th International Conference on Optical Communications and Networks, Nanjing, China, 2010, pp. 103–107.Google Scholar
- C. B. Cameron, R. M. Keolian, and S. L. Garrett, “A symmetric analogue demodulator for optical fiber interferometric sensors,” in Proceeding of IEEE Symposium on Circuits and Systems, Monterey, CA, USA, 1991, pp. 666–671.Google Scholar
- Z. F. Wang, H. Luo, and Y. M. Hu, “Signal detection technique for fiber-optic interferometric sensors,” Journal of Applied Optics, 2007, 28(1): 86–91.Google Scholar
Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.