Long-term Persistence of Rayleigh Signature of Optical Fibers in Harsh Environment

This paper investigates the persistence of Rayleigh signatures in optical sensing fibers installed in harsh environments. We show that the measurements taken from some fibers installed in rough conditions still retain the Rayleigh signature after more than six years, even though those measurements have been collected with different Optical Frequency Domain Reflectometry interrogators and setups. To this aim, we rely on the Spectral Correlation Analysis, which compares and spectrally correlates the fiber's Rayleigh-backscattered trace despite the usage of different interrogator and their spatial misalignment.