Simultaneous Measurement Of Temperature And Strain With A Bragg Grating Sensor In Polarization-Maintaining Fiber

Abstract

This study aims to develop a reliable technique that enables fiber optic sensors to decouple strain and temperature effects, making them viable for real-world industrial applications. While current solutions demonstrate promising results in laboratory settings, they often lack robustness for integration into operational environments. The proposed approach leverages Fiber Bragg Grating sensors inscribed in polarization-maintaining fibers. The birefringent nature of these fibers produces two distinct Bragg reflections along orthogonal polarization axes, enabling accurate thermo-mechanical separation with a single sensing element. A dedicated experimental setup was designed to calibrate and test the sensors under controlled thermal and mechanical loads. Finite element models were used to study optimal fiber orientation for integration into composite structures. Tests identified the 45? orientation of the optical fiber section relative to the composite material section as the most balanced configuration, minimizing the need for recalibration post-embedding. Preliminary experimental results and simulations indicate that this type of sensors can reliably discriminate between thermal and mechanical influences. Future works include further data analysis to improve the sensing system's resolution and the development of more detailed models based on the Finite Element Method, supported by additional experimental validations.