Abstract

A sensing system is proposed for quantitative and large-range measurement of dynamic nano-strain based on phase-sensitive optical time domain reflectometer (Φ-OTDR). The coherent detection and IQ demodulation methods are employed into the Φ-OTDR system to demodulate the phase of Rayleigh scattering light in real-time. By measuring phase differences between two adjacent sections, the nano-strain of quantitative and large strain measurement range is for the first time realized. The strain sensing range is 10-1000 nε, the strain resolution is 1 nε, the spatial resolution is 5 m, the strain parameter of phase is measured to be 0.04357 rad/nε, the strain-parameter of refractive index k is measured to be −0.3751 ε−1 and the frequency response is 185 Hz.

© 2016 Optical Society of America