We demonstrate the enlargement of sensing range of Brillouin optical correlation domain analysis (BOCDA) system by introducing the first-order distributed Raman amplification. The time-domain data processing is adopted for the BOCDA system utilizing a gated Brillouin pump, and the Raman amplification is applied to compensate for the depletion of Brillouin pump induced by Rayleigh scattering and Brillouin interaction. The Raman pump is injected in the opposite direction to the propagation of Brillouin pump, where the pumping scheme is optimized by simulations. A differential measurement scheme is additionally introduced for improving spatial resolution and dynamic range. In experiments, we measure the strain distribution along a 52.1 km sensing fiber with 7 cm spatial resolution, where the number of resolving points of measurement is more than 744 000.
- Optical fiber sensor
- Raman scattering
- Stimulated brillouin scattering
- time domain analysis
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics