Optical Signal Attenuation in an FBG Sensor Network for Aerospace Systems Monitoring

Abstract In the field of aerospace systems monitoring, Fiber Bragg Grating (FBG) sensors have emerged as a promising technology due to their high sensitivity, multiplexing capability and immunity to electromagnetic interference. However, the design and implementation of an FBG-based optical sensor network for systems monitoring present significant challenges, particularly related to signal attenuation. Optical signal losses, resulting from multiple factors such as fiber curvature, splices, connectors, feedthroughs, and the number of FBGs in the network, can critically affect the accuracy and reliability of the acquired data. This paper presents an initial investigation into the optical signal attenuation mechanisms in FBG sensor networks for aerospace applications. The ultimate objective of this study is to support the preliminary design phase of such networks by developing a predictive tool capable of estimating the total signal attenuation as a function of the geometric configuration of the network. To this end, firstly a comprehensive literature review was conducted, focusing on the main sources of attenuation, including bending losses due to fiber curvature, junction and insertion losses, and the cumulative effects of multiple FBGs in a single network. Building on this bibliographic analysis, the authors propose the development of a computational algorithm designed to estimate the overall optical signal attenuation in a given FBG sensor network. The algorithm incorporates input parameters such as the number and type of splices, the presence of feedthroughs, the number and location of FBGs, connector characteristics, and fiber curvature radii along the path. The aim is to provide designers with a practical and scalable tool to evaluate signal integrity at the early stages of sensor network design, helping to ensure optimal placement and minimal signal degradation throughout the system.