Fast and high spatial resolution distributed optical fiber sensor

摘要

Distributed optical fiber sensors (DOFS) based on stimulated Brillouin scattering (SBS) are increasingly gaining popularity due to their vast practical applications. There have been a lot of Brillouin-based distributed fiber sensing methods proposed so far but they suffer from a trade-off between spatial resolution, dynamic range and measurement time. In this paper, we propose a scanning-free Brillouin optical time domain analyzer (BOTDA) based on multiple short pulse stimulated Brillouin scattering. The accumulation of acoustic phonons which are stimulated due to the passage of successive pico-second pulses along the sensing fiber causes the sub-centimeter spatial resolution and kilometer dynamic range can be achieved simultaneously in our proposed technique called multiple short pulse BOTDA (MSP-BOTDA). Moreover, since the effective Brillouin gain bandwidth of pump pulse train is more than the natural SBS bandwidth, a wider range of temperature/strain changes can be detectable by MSP-BOTDA technique compared to conventional BOTDA method.