Ultra-high sensitivity strain sensor based on biconical fiber with a bulge air-bubble

An ultra-high sensitivity Fabry-Perot interferometer (FPI) strain sensor is proposed and experimentally demonstrated. It is composed of a biconical fiber with a bulge air-bubble at its waist. Because of the good stress concentration capability of the tapered fiber, the bulge air-bubble is easily deformed when it is stressed, resulting in an ultra-high strain sensitivity of 101.7 pm/mu epsilon, which is the highest strain sensitivity among the direct wavelength interrogation-based strain sensors reported so far, to the best of our knowledge. Moreover, the proposed sensor has a low temperature sensitivity of similar to 1 pm/degrees C; thus an extreme low temperature cross sensitivity of less than 10 n epsilon/degrees C can be achieved. (C) 2021 Optical Society of America

Automated summary

An ultra-high sensitivity Fabry-Perot interferometer (FPI) strain sensor with a bulge air-bubble at its waist is proposed and demonstrated in this research. The sensor shows an ultra-high strain sensitivity of 101.7 pm/mu epsilon, which is the highest among direct wavelength interrogation-based strain sensors reported so far. Additionally, it also has a low temperature sensitivity of around 1 pm/degrees C, achieving an extremely low temperature cross sensitivity of less than 10 n epsilon/degrees C.