Suppression of ghost correlation peak in Brillouin optical correlation-domain reflectometry

In Brillouin optical correlation-domain reflectometry (BOCDR), an undesired "ghost" correlation peak is automatically generated at the open end of a sensing fiber in addition to the desired correlation peak used for distributed measurement. The Brillouin spectrum of the light scattered from this ghost peak, which has a fixed position, overlaps that from the desired peak, inducing noise and lowering the signal-to-noise ratio. The importance of ghost-peak suppression is experimentally shown by demonstrating that a distributed strain measurement can only be successful when a bending loss of 6 dB or larger is applied near the open end.