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High-resolution extended distance distributed fiber-optic sensing using Rayleigh backscatter

We describe the use of swept-wavelength interferometry for distributed fiber-optic sensing in single- and multimode optical fiber using intrinsic Rayleigh backscatter. The interrogation technique is based on measuring the spectral shift of the intrinsic Rayleigh backscatter signal along an unaltered standard telecommunications grade optical fiber and converting the spectral shift to strain or temperature. This technique shows great utility as a method for highly distributed sensing over great distances with existing, pre-installed optical fiber. Results from sensing lengths greater than 1 km of optical fiber with spatial resolutions better than 10 cm are reported.