Compact FBG strain sensor for an accurate measurement method with wide-range temperature compensation

Cross-sensitivity between strain and temperature is a thorny issue in fiber Bragg grating (FBG) sensing. Especially, due to the mismatch between the thermal expansion coefficients of the adhesive and the FBG, the effect of temperature is magnified even more when FBG strain is packaged with certain adhesives. To solve this problem, a specially designed strain sensor with wide-range temperature compensation is developed in this paper. The FBG strain sensor had a length of 18 mm and a weight of 0.35 g. Its sensitivity was calculated to be 1.35 pm/με, with excellent linearity (R² = 0.99951). Through experimental test and data analysis, the sensor demonstrated a temperature sensitivity of 29.8 pm/℃ within the -50 ℃ to 150 ℃ range, accompanied by a linear regression coefficient (R²) of 0.9979, and maintained stable performance over thermal cycles. Post-compensation analysis revealed strain measurement accuracy exceeding 99% after temperature interference elimination. This sensor enables real-time thermal compensation for wing load monitoring, enhancing structural safety.