Distributed optical fiber strain and temperature sensing system performances: Brillouin vs Rayleigh

Both Rayleigh and Brillouin scatterings measurements in optical fibers are able to provide distributed strain and temperature profiles. Acquisition parameters, measurement quality, impact of the environment over time, effective spatial resolution obtained on field are some of the driving specifications. We report here some studies on Brillouin and Rayleigh scattering techniques, related to their performances concerning measurement quality, distance range and spatial resolution. Even if Rayleigh-based measurements are more accurate with 6 µe uncertainty (versus 17 μe), Brillouin-based methods are more reliable than Rayleigh-based on cross-correlation for strain difference over 500 μe; while with the same parameters Rayleigh-based systems are able to provide a higher effective spatial resolution.