[1] [1] Lü Yuelan, Xing Yongwei. Investigation on rayleigh scattering waveform in phase optical time domain reflectometer［J］. Acta Optica Sinica, 2011,31(8): 0819001.

[2] [2] He H J, Shao L Y, Li Z L, et al. Self-mixing demodulation for coherent phase-sensitive OTDR system［J］. Sensors, 2016, 16(5): 681-691.

[3] [3] 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.

[4] [4] Martins H F, Martin-Lopez S, Corredera P, et al. Phase-sensitive optical time domain reflectometer assisted by first-order Raman amplification for distributed vibration sensing over >100 km［J］. Journal of Lightwave Technology, 2014, 32(8): 1510-1518.

[5] [5] Tayler H F, Lee C E. Apparatus and method for fiber optic intrusion sensing: 5194847［P］. 1993-3-16.

[6] [6] Li Y, Zhou Y, Zhang L, et al. Phase-sensitive optical time-domain reflectometry amplified by gated Raman pump［J］. Photonic Sensors, 2015, 5(4): 345-450.

[7] [7] Zhou Jun, Pan Zhengqing, Ye Qing, et al. Phase demodulation technology using a multi-frequency source for discrimination of interference-fading induced false alarms in a φ-OTDR system［J］. Chinese J Lasers, 2013, 40(9): 0905003.

[8] [8] Wang Z Y, Pan Z Q, Fang Z J, et al. Ultra-broadband phase-sensitive optical time-domain reflectometry with a temporally sequenced multi-frequency source［J］. Optics Letters, 2015, 40(22): 5192-5195.

[9] [9] Zhang M, Wang S, Zheng Y W, et al. Enhancement for φ-OTDR performance by using narrow linewidth light source and signal processing［J］. Photonic Sensors, 2016, 6(1): 58-62.

[10] [10] Liang Kezhen, Pan Zhengqing, Zhou Jun, et al. Multi-parameter vibration detection system based on phase sensitive optical time domain reflectometer［J］. Chinese J Lasers, 2012, 39(8): 0805004.

[11] [11] Pan Z Q, Liang K Z, Ye Q, et al. Phase-sensitive OTDR system based on digital coherent detection［C］. SPIE, 2011, 8311: 83110S.

[12] [12] Pang F F, He M T, Liu H H, et al. A fading-discrimination method for distributed vibration sensor using coherent detection of φ-OTDR［J］. IEEE Photonics Technology Letters, 2016, 28(23): 2752-2755.