[1] Feng K B, Song M P, Xia Q L et al. High-resolution distributed optical-fiber sensing technology based on direct-detecting coherent optical time-domain reflectometer[J]. Acta Optica Sinica, 36, 0106002(2016).

[2] Bao X, Zhou D P, Baker C. et al. Recent development in the distributed fiber optic acoustic and ultrasonic detection[J]. Journal of Lightwave Technology, 35, 3256-3267(2017). http://ieeexplore.ieee.org/document/7572132/

[3] Sergi V, Joanr C. Application of optical fiber distributed sensing to health monitoring of concrete structures[J]. Mechanical Systems and Signal Processing, 39, 441-451(2013). http://www.sciencedirect.com/science/article/pii/S0888327012000283

[4] Le Y F, Ju A S. Analysis and measurement of the nonlinear errors in heterodyne interferometers[J]. Laser & Optoelectronics Progress, 53, 051203(2016).

[5] Wei P, Shan X K, Sun X H. Frequency response of distributed fiber-optic vibration sensor based on nonbalanced Mach-Zehnder interferometer[J]. Optical Fiber Technology, 19, 47-51(2013). http://www.sciencedirect.com/science/article/pii/S1068520012001435

[6] Wada K, Narui H, Yamamoto D. et al. Balanced polarization maintaining fiber Sagnac interferometer vibration sensor[J]. Optics Express, 19, 21467-21474(2011). http://europepmc.org/abstract/MED/22108996

[7] Russell S J, Brady K R, Dakin J P. Real-time location of multiple time-varying strain disturbances, acting over a 40-km fiber section, using a novel dual-Sagnac interferometer[J]. Journal of Lightwave Technology, 19, 205-213(2001). http://www.opticsinfobase.org/abstract.cfm?uri=JLT-19-2-205

[8] Kondrat M, Szustakowski M, Palka N. et al. A Sagnac-Michelson fibre optic interferometer: signal processing for disturbance localization[J]. Opto-Electronics Review, 15, 127-132(2007). http://link.springer.com/article/10.2478/s11772-007-0012-x

[9] Bao X Y, Chen L. Recent progress in distributed fiber optic sensors[J]. Sensors, 12, 8601-8639(2012). http://europepmc.org/articles/PMC3444066/

[10] Zhang C X, Zhong X, Li L J. et al. Long-distance intrusion sensor based on phase sensitivity optical time domain reflectometry[J]. Infrared and Laser Engineering, 44, 742-746(2015). http://www.researchgate.net/publication/282179833_Long-distance_intrusion_sensor_based_on_phase_sensitivity_optical_time_domain_reflectometry

[11] Ding X X, Zhang X, Wang H B. et al. Influences of modulation frequency on dynamic performance of vibration sensor based on φ-OTDR[J]. Infrared and Laser Engineering, 44, 210-214(2015).

[12] Hui X N, Zheng S L, Zhou J H. Electro-optic modulator feedback control in phase-sensitive optical time-domain reflectometer distributed sensor[J]. Applied Optics, 52, 8581-8584(2013). http://www.ncbi.nlm.nih.gov/pubmed/24513905

[13] Peng F, Wu H, Jia X H. et al. Ultra-long high-sensitivity φ-OTDR for high spatial resolution intrusion detection of pipelines[J]. Optics Express, 22, 13804-13810(2014).

[14] Liang S, Liu T F, Sheng X Z et al. Investigation on space-domain difference based location method for φ-OTDR fiber-optic distributed disturbance sensor[J]. Infrared and Laser Engineering, 45, 0622005(2015).

[15] Lu Y L, Zhu T. Distributed vibration sensor based on coherent detection of phase-OTDR[J]. Journal of Light Wave Technology, 28, 3243-3249(2010). http://ieeexplore.ieee.org/document/5585644/

[16] Koyamada Y, Imahama M, Kubota K. et al. Fiber-optic distributed strain and temperature sensing with very high measurand resolution over long range using coherent OTDR[J]. Journal of Lightwave Technology, 27, 1142-1146(2009). http://www.opticsinfobase.org/abstract.cfm?uri=JLT-27-9-1142

[17] Nakazawa M. Rayleigh backscattering theory for single-mode optical fibers[J]. Journal of the Optical Society of America, 73, 1175-1180(1983). http://www.opticsinfobase.org/abstract.cfm?id=58865

[18] Juskaitis R. Interferometry with Rayleigh backscattering in a single-mode optical fiber[J]. Optics Letters, 19, 225-227(1994). http://www.opticsinfobase.org/ol/abstract.cfm?uri=ol-19-3-225

[19] Todd M D, Seaver M, Bucholtz F. Improved, operationally-passive interferometric demodulation method using 3×3[J]. Electronics Letters, 38, 784-786(2002).