High-Speed Mach-Zehnder-OTDR Distributed Optical Fiber Vibration Sensor Using Medium-Coherence Laser

Abstract

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.

Keywords

High-speed / Mach-Zehnder-OTDR / ultra-weak fiber Bragg grating array / medium-coherence laser / optical fiber vibration sensing

References

[1] Bao X., Zhou D. P., Baker C., Chen L.. Recent development in the distributed fiber optic acoustic and ultrasonic detection. Journal of Lightwave Technology, 2017, 35(16): 3256-3267.

[2] Li Z. Y., Liu M. Y., Wang Y. M., Liu Q., Gong J. M.. Delay calibration method for wavelength-swept laser-based FBG demodulation system. IEEE Photonics Technology Letters, 2014, 26(20): 2090-2092.

[3] Luo Z. H., Wen H. Q., Guo H. Y., Yang M. H.. A time- and wavelength-division multiplexing sensor network with ultra-weak fiber Bragg gratings. Optics Express, 2913, 21(19): 22799-22807.

[4] Li Z. Y., Xu Z. Q., Tang Z. H., Zhao M., Cai L. J., Liu Q.. Research of high-speed FBG demodulation system for distributed dynamic monitoring of mechanical equipment. Advances in Mechanical Engineering, 2013, 7, 679-681.

[5] Hong X. B., Guo H. X., Wu J.. A Brillouin optical time domain analysis based distributed fiber optic intrusion sensor system. Chinese Journal of Lasers, 2010, 37(37): 1037-1041.

[6] Lu Y. L., Zhu T., Chen L., Bao X. Y.. Distributed vibration sensor based on coherent detection of phase-OTDR. Journal of Lightwave Technology, 2010, 28(22): 3243-3249.

[7] Gunday A., Karlik S. E.. 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, 2013, Turkey: Bursa, 14-15.

[8] Wang Y. N., Jiang Z. D.. Application of Golay codes to distributed optical fiber sensor for long-distance oil pipeline leakage and external damage detection. Chinese Optics Letters, 2006, 4(3): 141-144.

[9] Ma C. Y., Liu T. G., Liu K., Jing J. F., Ding Z. Y., Pan L., . Long-range distributed fiber vibration sensor using an asymmetric dual Mach-Zehnder interferometers. Journal of Lightwave Technology, 2016, 34(9): 2235-2239.

[10] Zhang C. X., Li Q., Liang S., Lin W. T., Li L. J., Zhang X.. 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, 2010, China: Nanjing, 103-107.

[11] Juarez J. C., Taylor H. F.. Distributed fiber optic intrusion sensor system. Journal of Lightwave Technology, 2015, 23(6): 2081-2087.

[12] Koyamada Y., Imahama M., Kubota K., Hogari K.. Fiber-optic distributed strain and temperature sensing with very high measurand resolution over long range using coherent OTDR. Journal of Lightwave Technology, 2009, 27(9): 1142-1146.

[13] Masoudi A., Belal M., Newson T. P.. A distributed optical fiber dynamic strain sensor based on phase-OTDR. Measurement Science & Technology, 2013, 24(8): 085204.

[14] Zhu T., He Q., Xiao X. H., Bao X. Y.. Modulated pulses based distributed vibration sensing with high frequency response and spatial resolution. Optics Express, 2013, 21(3): 2953.

[15] He Q., Zhu T., Xiao X. H., Zhang B. M., Diao D. M., Bao X. Y.. All fiber distributed vibration sensing using modulated time-difference pulses. IEEE Photonics Technology Letters, 2013, 25(20): 1955-1957.

[16] Wang C., Shang Y., Liu X. H., Wang C., Yu H. H., Jia D. S., . Distributed OTDR-interferometric sensing network with identical ultra-weak fiber Bragg gratings. Optics Express, 2015, 23(22): 29038-29046.

[17] Cameron C. B., Keolian R. M., Garrett S. L.. A symmetric analogue demodulator for optical fiber interferometric sensors. in Proceeding of IEEE Symposium on Circuits and Systems, 1991, CA, USA: Monterey, 666-671.

[18] Wang Z. F., Luo H., Hu Y. M.. Signal detection technique for fiber-optic interferometric sensors. Journal of Applied Optics, 2007, 28(1): 86-91.

[19] Zhu F., Zhang Y. X., Xia L., Wu X. L., Zhang X. P.. Improved F-OTDR sensing system for high-precision dynamic strain measurement based on ultra-weak fiber Bragg grating array. Journal of Lightwave Technology, 2015, 33(23): 4775-4780.