Theoretical and experimental study on crosstalk caused by multiple reflections in identical weak fiber Bragg grating array

Abstract

Large scale distributed sensor networks based on fiber Bragg gratings (FBGs) can find a wide range of uses. However, when identical FBGs are connected in series, the crosstalk will occur because of multiple reflections among the FBGs. In this article, theoretical simulations were done on the crosstalk in an array with FBG peak reflectivity of -35dB. An array consisting of identical weak FBGs with peak reflectivities ranging from -33dB to -37dB and a spatial resolution of 2.5m was prepared in-line on a fiber draw tower. The testing results of the FBG array are in close agreement with the theoretical simulations and ghost gratings can be observed on the reflection spectrum of the FBG array.