[1] BAO X Y, CHEN L. Recent progress in distributed fiber optic sensors[J]. Sensors, 2012, 12(7): 8601-8639. doi: 10.3390/s120708601
[2] JUAREZ J C, MAIER E W, CHOI K N, et al. Distributed fiber-optic intrusion sensor system[J]. Journal of Lightwave Technology, 2005, 23(6):2081-2087. doi: 10.1109/JLT.2005.849924
[3] YILMAZ G, KARLIK S E. A distributed optical fiber sensor for temperature detection in power cables[J]. Sensors and Actuators, 2006, A125(2): 148-155.
[4] PENG F, DUAN N, RAO Y J, et al. Real-time position and speed monitoring of trains using phase-sensitive OTDR[J]. IEEE Photonics Technology Letters, 2014, 26(20): 2055-2057. doi: 10.1109/LPT.2014.2346760
[5] ZOU D B, LIU H, ZHAO L, et al. Research on distributed optical fiber vibration sensing signal recognition[J]. Laser Technology, 2016, 40(1):86-89(in Chinese).
[6] JUAREZ J C, TAYLOR H F. Field test of a distributed fiber-optic intrusion sensor system for long perimeters[J]. Applied Optics, 2007, 46(11): 1968-1971. doi: 10.1364/AO.46.001968
[7] ZHOU L, WANG F, WANG X Ch, et al. Distributed strain and vibration sensing system based on phase-sensitive OTDR[J]. IEEE Photonics Technology Letters, 2015, 27(17): 1884-1887. doi: 10.1109/LPT.2015.2444419
[8] WATKINS S E. Smart bridges with fiber-optic sensors[J]. IEEE Instrumentation & Measurement Magazine, 2003, 6(2): 25-30.
[9] HEALEY P. Fading in heterodyne OTDR[J]. Electronics Letters, 1984, 20(1): 30-32. doi: 10.1049/el:19840022
[10] BARNOSKI M K, ROURKE M D, JENSEN S M, et al. Optical time domain reflectometer[J]. Applied Optics, 1977, 16(9): 2375-2379. doi: 10.1364/AO.16.002375
[11] DANIELSON B L. Optical time-domain reflectometer specifications and performance testing[J]. Applied Optics, 1985, 24(15): 2313-2322.
[12] WANG M Y, SHENG L, TAO Y, et al. Influence of laser linewidth on the performance of ϕ-OTDR system[J]. Laser Technology, 2016, 40(4):615-618(in Chinese).
[13] PAN Zh Q, LIANG K Zh, YE Q, et al. Phase-sensitive OTDR system based on digital coherent detection[J]. Proceedings of the SPIE, 2011, 8311:1-6.
[14] LIANG K Zh, PAN Zh Q, ZHOU J, et al. Multi-parameter vibration detection system based on phase sensitive optical time domain reflectometer[J]. Chinese Journal of Lasers, 2012, 39(8):0805004(in Chinese). doi: 10.3788/CJL
[15] MASOUDI A, BELAL M, NEWSON T P, et al. A distributed optical fibre dynamic strain sensor based on phase-OTDR[J]. Measurement Science and Technology, 2013, 24(8): 085204. doi: 10.1088/0957-0233/24/8/085204
[16] ALEKSEEV A E, VDOVENKO V S, GORSHKOV B G, et al. A phase-sensitive optical time-domain reflectometer with dual-pulse diverse frequency probe signal[J]. Laser Physics, 2014, 24(24):115106.
[17] WANG Ch, WANG Ch, SHANG Y, et al. Distributed acoustic mapping based on interferometry of phase optical time-domain reflectometry[J]. Optics Communications, 2015, 346: 172-177 doi: 10.1016/j.optcom.2015.02.044
[18] WANG C, SHANG Y, LIU X, et al. Distributed OTDR-interferometric sensing network with identical ultra-weak fiber Bragg gratings[J]. Optics Express, 2015, 23(22): 29038-29046. doi: 10.1364/OE.23.029038
[19] FANG G Sh, XU T W, FENG Sh W, et al. Phase-sensitive optical time domain reflectometer based on phase-generated carrier algorithm[J]. Journal of Lightwave Technology, 2015, 33(13): 2811-2816. doi: 10.1109/JLT.2015.2414416
[20] SHANG Y, YANG Y H, WANG Ch, et al. Optical fiber distributed acoustic sensing based on the self-interference of Rayleigh backscattering[J]. Measurement, 2016, 79:222-227. doi: 10.1016/j.measurement.2015.09.042
[21] WANG Z N, ZHANG L, WANG S, et al. Coherent ϕ-OTDR based on I/Q demodulation and homodyne detection[J]. Optics Express, 2016, 24(2): 853-858. doi: 10.1364/OE.24.000853
[22] MARTINS H F, SHI K, THOMSEN B C, et al. Real time dynamic strain monitoring of optical links using the backreflection of live PSK data[J]. Optics Express, 2016, 24(19): 22303-22318. doi: 10.1364/OE.24.022303
[23] FAN X Y, YANG G Y, WANG Sh, et al. Distributed fiber-optic vibration sensing based on phase extraction from optical reflectometry[J]. Journal of Lightwave Technology, 2017, 35(16): 3281-3288. doi: 10.1109/JLT.2016.2604859
[24] YANG G Y, FAN X Y, WANG Sh, et al. Long-range distributed vibration sensing based on phase extraction from phase-sensitive OTDR[J]. IEEE Photonics Journal, 2016, 8(3): 1-12.
[25] TU G J, ZHANG X P, ZHANG Y X, et al. The development of an ϕ-OTDR system for quantitative vibration measurement[J]. IEEE Photonics Technology Letters, 2015, 27(12): 1349-1352. doi: 10.1109/LPT.2015.2421354
[26] ZHU F, ZHANG Y X, XIA L, et al. Improved ϕ-OTDR sensing system for high-precision dynamic strain measurement based on ultra-weak fiber Bragg grating array[J]. Journal of Lightwave Technology, 2015, 33(23): 4775-4780. doi: 10.1109/JLT.2015.2477243
[27] TIAN Ch D, ZHANG H Y, ZHANG M, et al. Performance improvement of phase-generated carrier method by eliminating laser-intensity modulation for optical seismometer[J]. Optical Engineering, 2010, 49(2):193-213.
[28] LIU Y, WANG L W, TIAN Ch D, et al. Analysis and optimization of the PGC method in all digital demodulation systems[J]. Journal of Lightwave Technology, 2008, 26(18): 3225-3233. doi: 10.1109/JLT.2008.928926
[29] DANDRIDGE A, TVETEN A B, GIALLORENZI T G, et al. Homodyne demodulation scheme for fiber optic sensors using phase generated carrier[J]. IEEE Journal of Quantum Electronics, 1982, 18(10): 1647-1653. doi: 10.1109/JQE.1982.1071416
[30] HE J, WANG L, LI F, et al. An ameliorated phase generated carrier demodulation algorithm with low harmonic distortion and high stability[J]. Journal of Lightwave Technology, 2010, 28(22): 3258-3265.
[31] BREGUET J, GISIN N. Interferometer using a 3×3 coupler and Faraday mirrors[J]. Optics Letters, 1995, 20(12): 1447-1449. doi: 10.1364/OL.20.001447
[32] TODD M D, SEAVER M, BUCHOLTZ F. Improved, operationally-passive interferometric demodulation method using 3×3 coupler[J]. Electronics Letters, 2002, 38(15):784-786. doi: 10.1049/el:20020569
[33] SHEEM S K. Optical fiber interferometers with[3×3] directional couplers: Analysis[J]. Journal of Applied Physics, 1981, 52(6):3865-3872. doi: 10.1063/1.329853
[34] WU F, WU B K, YU W Zh, et al. Design of fiber optic sound sensor based on phase demodulation of 3×3 coupler[J]. Laser Technology, 2016, 40(1):64-67(in Chinese).
[35] XU D, YANG F, CHEN D J, et al. Laser phase and frequency noise measurement by Michelson interferometer composed of a 3×3 optical fiber coupler[J]. Optics Express, 2015, 23(17):22386. doi: 10.1364/OE.23.022386
[36] TAYLOR M G. Phase estimation methods for optical coherent detection using digital signal processing[J]. Journal of Lightwave Technology, 2009, 27(7): 901-914. doi: 10.1109/JLT.2008.927778
[37] HO K C, CHAN Y T, INKOL R, et al. A digital quadrature demodulation system[J]. IEEE Transactions on Aerospace and Electronic Systems, 1996, 32(4): 1218-1227. doi: 10.1109/7.543843
[38] LU Y L, ZHU T, CHEN L, et al. Distributed vibration sensor based on coherent detection of phase-OTDR[J]. Journal of Lightwave Technology, 2010, 28(22): 3243-3249.
[39] IP E, LAU A P, BARROS D J, et al. Coherent detection in optical fiber systems[J]. Optics Express, 2008, 16(2): 753-791. doi: 10.1364/OE.16.000753