Research papers - IEEE Sensors Journal ( Volume: 22, Issue: 12, 15 June 2022)
A CDM-WDM Interrogation Scheme for Massive Serial FBG Sensor Networks
Marek Götten, Steffen Lochmann, Andreas Ahrens, Eric Lindner, Johan Vlekken, Jan Van Roosbroeck
Short description
Structural health monitoring and other smart structures gain an increased attention which can be satisfied by the quasi-distributed optical sensing approach. Serial fiber optic sensors, such as fiber-Bragg gratings (FBGs) provide among others small size, immunity to electro-magnetic interference, an accurate sensing accuracy and a high multiplexing capability to increase the amount of sensing points in an optical sensor network. Different multiplexing approaches demonstrated a limited number of FBGs, such as time-division multiplex, optical frequency domain refractometry or frequency shifted interferometry. This work introduces a code-division multiplex (CDM) - wavelength-division multiplex (WDM) interrogator for massive serial FBG sensor networks. The interrogation of 4000 serial sensors in a network with a length of 113m, 200 identical WDM sections over a length of 200m and a network with 1000 sensors and a length of 1.6km show a massive multiplexing capability of up to 16000 sensors and possible network lengths of several kilometers. Strain measurements with FBGs in rear sections prove the sensing applicability of the CDM-WDM scheme