Abstract: Brillouin optical time domain analysis (BOTDA) has unique advantages in measuring precision and spatial resolution due to stimulated amplification of Brillouin scattering. When BOTDA-based distributed fiber optic sensors are applied to strain monitoring of structures, the Brillouin frequency shift is sensitive to both strain and temperature. To eliminate the influence of temperature on strain, a temperature compensation method based on BOTDA is herein proposed. The temperature-compensated structural strain can be obtained from the strain recorded from the integrated cable including optical fibers of both temperature sensing and strain sensing without involving the temperature. The installation and data processing are convenient to be conducted with favorable information synchronizing and environmental suitability as well as low cost. The proposed method has significant advantages in comparison with existing temperature compensation methods and is validated by indoor water bath tests and field tests for a drainage pumping station during construction.

Key words: distributed fiber optic sensing, Brillouin optical time domain analysis, temperature compensation, structural health monitoring, pumping station