Evaluation of effective elastic modulus of optical fiber by using FBG sensor

Tensile tests of optical fibers and vibration tests of optical fiber rings have been conducted to measure the exact physical properties of optical fibers and optical fiber sensors. However, there have been few studies using optical fibers themselves as measurement sensors. In this study, we propose a free vibration test using an FBG sensor embedded in an optical fiber and a method to estimate the mechanical properties of the optical fiber sensor from the measured natural frequency. The proposed method does not require additional equipment such as tensile tester and can easily evaluate the mechanical characteristics even with the FBG sensor strain measuring equipment already provided. Therefore, it is expected to be used for checking the physical properties of the optical fiber itself and the properties of the recoated optical fiber. In order to analyze the natural frequency of the optical fiber, we compared the experimental results with the finite element method and evaluated the elastic modulus from the natural frequency of the optical fiber.