온도 보상형 FBG 변형률 센서 개발을 위한 EDF 온도 특성 평가

초록

FBG sensors containing capability of multiplexing are often used to measure thermal and strain of structures exposed to harsh environments. However, temperature compensation using a thermocouple is required for FBG sensors to measure the strain in condition of temperature changes because the demodulation principle of them is a function of strain and temperature. So, there are rising concerns on FBG strain sensors that do not require additional sensors for temperature compensation. In this paper, as a fundamental study, thermal characteristics of erbium-doped fibers (EDF) are investigated to develop an FBG strain sensor with autonomous temperature compensation. For the test, the change of light absorption ratio is examined when the length of EDF is changed from 1m to 3m and the temperature is changed from RT to 100℃, respectively. From the test results, light absorption ratio of EDF is proportional to both the length of EDF and temperature change. Consequently, on the basis of experimental results, it is confirmed that an FBG strain sensor with autonomous temperature compensation can be developed using the relation between light absorption and temperature change.