Contents 1. Introduction
Fiber optic distributed sensors are becoming increasingly attractive for temperature and strain monitoring over short, medium and long-distance applications. In particular, the main advantage of fiber-based distributed temperature sensors, compared to conventional or point sensors, mainly lies in their unparalleled ability to continuously and accurately monitor the temperature over long sensing distances with high spatial resolution. Compared to the most commercially successful solution based on spontaneous Raman scattering, Brillouin based distributed sensors offer the attractive possibility to monitor both temperature and strain simultaneously [1]; in particular, Brillouin-based distributed temperature sensors (BDTS) are characterized by higher backscattering intensities and lower temperature sensitivity compared to Raman-based DTS, but they also require a more complex receiver structure. BDTS can be implemented using either spontaneous or stimulated Brillouin scattering; while spontaneous-BDTS require simpler implementation schemes [1], stimulated-BDTS allows for higher accuracy and resolution in the measurement but also requires access to both fiber ends and more complex detection [2].
