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.

Fast and high spatial resolution distributed optical fiber sensor

Stable trains of Stokes pulses with the unusually short duration of approximately=200 ps were obtained, using a simple Brillouin fiber ring laser with standard single-mode, Ge-doped fiber. They were achieved by confining the fiber in the resonator, which resulted in reduced threshold and increased output power. This threshold reduction nontrivially allowed substantially shorter pump pulses (500-100 ps) to be used, and, as a result, extremely short Stokes pulses were generated. >

Extremely transient pulses from a Brillouin fiber laser

The authors have experimentally observed for the first time an efficient Brillouin scattering of a train of short pulses in single-mode optical fibres

N I Minkovski

Papers

Stimulated Brillouin scattering of short pulses by phonon accumulation in optical fibres