Influence of reference path length on self‐heterodyne‐based Brillouin observation

Abstract

AbstractFibre‐optic distributed Brillouin sensing that utilises correlation‐domain techniques often requires an optical delay fibre in the reference path to control the correlation peak order in the sensing fibre. Nonetheless, a suboptimal delay fibre length can result in decreased performance. In this work, as a first step towards clarifying the optimal delay fibre length for Brillouin correlation‐domain sensing, the authors evaluate the effect of changing the delay fibre length on the Brillouin gain spectra in a full‐length measurement scenario.