Designing of FBG Based Sensor Networks for Long-Distance Monitoring Solutions

A lot of new infrastructure projects are made with ever-increasing demands for safety and ease of maintenance. By using relatively easy-to-integrate and effective optical sensors such as optical fiber Bragg grating (FBG) ones, it is possible to construct networks of 50 km long measurement lines. These sensors have other advantages that make them ideal for large sensing networks such as their immunity to electromagnetic interference, passive nature, remote sensing ability and possibility for multiplexing. Due to the uniformity of FBG sensors, such a network is compatible with other network types that have also used integrated FBGs as a solution. The intrinsic longevity of FBG sensors — allowing the realization even if deformed, ensures that it is possible to provide long-term exploitation of the technology. This research focuses on showing how to use mathematical modelling and designing software to predict the caused effect of different apodizations on certain parameters — such as reflectivity, side lobe suppression (SLS) and full width at half maximum (FWHM), as well as comparing them at the scale of different networks. By simulating networks with different types of apodizations such as Gaussian, sine and raised sine, it is possible to gain insight into the most effective ways to configure large-scale structural health monitoring (SHM) networks that span over many kilometers. Results show that it is possible to ensure the achievement of higher efficiency for the realization of available limited bandwidth in such sensor solutions. Thus, also improving on development of larger scale monitoring networks, longer measurement distances and more individual sensors capabilities. Last but not least, significantly more detailed feedback on the deterioration of huge infrastructure projects such as roads, bridges, etc.