All-fiber system for simultaneous interrogation of distributed strain and temperature sensing by spontaneous Brillouin scattering

摘要

We demonstrate a low-loss, long-range, single-ended distributed optical fiber sensor to measure both temperature and strain simultaneously and unambiguously. By using the Landau-Placzek ratio and cascaded Mach-Zehnder interferometric filters, we measure both the intensity and the frequency changes in the Brillouin backscattered signal. Strain and temperature measurements can then be independently resolved. A temperature resolution of 4℃, a strain resolution of 290 μ∈, and a spatial resolution of 10 m have been achieved for a sensing length of 15 km.