High spatial resolution and long-distance BOTDA using differential Brillouin gain in a dispersion shifted fiber

Abstract

In a long-distance Brillouin sensing system, modulation instability (MI) effect could deplete the probe pulse at a high pulse power in a standard single-mode fiber, which decreases the Brillouin gain and signal-to-noise ratio, and thus limits the spatial resolution and sensing length. In this paper, a dispersion shifted fiber with normal dispersion is used to avoid the MI effect; a spatial resolution of 0.5 m is realized using differential Brillouin gain in a 25-km dispersion shifted fiber, to the best of our knowledge, which is the best value in such a length.