Quantitative measurement of disturbances based on optical-fibre multiparameter optimization method

Abstract

Phase-sensitive optical time domain reflectometry (φ-OTDR) has been applied in security monitoring. However, φ-OTDR cannot directly measure strain and intensity of an applied disturbance, thereby limiting the choice of features for intrusion pattern recognition and hazard assessment. This paper proposes a quantitative method to measure disturbances using amplitude-based φ-OTDR. The optical-fibre multiparameter optimization (FMPO) method is developed. The FMPO analyses the curve pattern of optical intensity signals to calculate strain. No extra module is needed, instead a specially designed bio-inspired algorithm is introduced. Quantification indices to gauge disturbance intensities are derived for practical use. A piezoelectric ceramic cylinder test demonstrated a linear correlation between the quantification indices and the vibration amplitude (R2 = 0.8956). The calculated strains of 34 driven voltages agreed well with theoretical values within 1000 nε. In a pendulum-impact experiment, five intrusion intensities were successfully identified, which indicated that FMPO performed well in the field.