A Low-Cost Technique for Simulation and Characterization of Fibre Bragg Grating Sensors in Undergraduate Instructional Laboratories

Fibre optic sensors are becoming so important in engineering that it is important to introduce this new subject in Electrical Engineering courses. This work describes the construction of a simple, low-cost fibre Bragg grating (FBG) electronic interrogation system that uses LabVIEW as a tool for simulation, measurement interface and parameter extraction of the FBGs. Although the system is relatively slow (a precise FBG characterization takes 10 minutes to be performed), the students can observe, while performing the assigned tasks, all the signals in the interrogator circuit, resulting in an extremely useful didactic tool. The measurements obtained with the system are in very good agreement with results measured on expensive Optical Spectrum Analysers when obtaining a full FBG profile. The system can also be used to measure and characterize FBGs submitted to external strains (e.g., temperature and force) demonstrating the Bragg shift caused by these strains on FBG sensors.