title: Self-Mixing Demodulation for Coherent Phase-Sensitive OTDR System.
abstract: Phase-sensitive optical time domain reflectometry (Ф-OTDR) attracts much attention due to its capability of telling the type and position of an intrusion simultaneously. In recent decades, coherent Ф-OTDR has been demonstrated to realize long-distance detection. For coherent Ф-OTDR, there are three typical demodulation schemes in the reported studies. However, they still cannot realize real-time monitoring to satisfy practical demands. A simple and effective demodulation method based on self-mixing has been put forward to demodulate the beat signal in coherent Ф-OTDR. It not only saves a local electrical oscillator and frequency locked loop, but also demodulates the beat signal without residual frequency. Several vibrations with different frequency were separately applied at the same location of a 42.5 km fiber. The spatial resolution of 10 m and frequency response range from 8 Hz to 980 Hz have been achieved. The precise location with signal-to-noise ratio of 21.4 dB and broadband measurement demonstrate the self-mixing scheme can demodulate the coherent Ф-OTDR signal effectively.
authors.affiliation: Center for Information Photonics & Communications, School of Information Science and Technology, Southwest Jiaotong University, Chengdu 610031, China. haijhe@163.com.
authors.forename: Haijun
authors.initials: H
authors.lastname: He
authors.affiliation: Center for Information Photonics & Communications, School of Information Science and Technology, Southwest Jiaotong University, Chengdu 610031, China. lyshao@home.swjtu.edu.cn.
authors.forename: Li-Yang
authors.initials: LY
authors.lastname: Shao
authors.affiliation: Center for Information Photonics & Communications, School of Information Science and Technology, Southwest Jiaotong University, Chengdu 610031, China. liz.onglei@163.com.
authors.forename: Zonglei
authors.initials: Z
authors.lastname: Li
authors.affiliation: Center for Information Photonics & Communications, School of Information Science and Technology, Southwest Jiaotong University, Chengdu 610031, China. zhiyongzhang@home.swjtu.edu.cn.
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Center for Information Photonics & Communications, School of Information Science and Technology, Southwest Jiaotong University, Chengdu 610031, China. zouxihua@swjtu.edu.cn.
authors.forename: Xihua
authors.initials: X
authors.lastname: Zou
authors.affiliation: Center for Information Photonics & Communications, School of Information Science and Technology, Southwest Jiaotong University, Chengdu 610031, China. bluo@home.swjtu.edu.cn.
authors.forename: Bin
authors.initials: B
authors.lastname: Luo
authors.affiliation: Center for Information Photonics & Communications, School of Information Science and Technology, Southwest Jiaotong University, Chengdu 610031, China. wpan@home.swjtu.edu.cn.
authors.forename: Wei
authors.initials: W
authors.lastname: Pan
authors.affiliation: Center for Information Photonics & Communications, School of Information Science and Technology, Southwest Jiaotong University, Chengdu 610031, China. lsyan@home.swjtu.edu.cn.
authors.forename: Lianshan
authors.initials: L
authors.lastname: Yan
keywords: fiber optics sensors; optical time domain reflectometry; remote sensing and sensors; scattering measurement