Strain sensor based on hollow microsphere Fabry-Perot cavity

Fusion splicing technique was explored for the fabrication of two sensing structures based on hollow microsphere Fabry- Perot cavity. The first sensor proposed was fabricated with a hollow microsphere tip, working as a probe sensor. This structure was studied for lateral load pressure, yielding a 1.56 ± 0.01 nm/N sensitivity. The second sensing structure relied on an in-line hollow microsphere, which allowed the detection of lateral load, with a sensitivity of 2.62 ± 0.02 nm/N. Furthermore, the proposed structure enabled strain sensing, with a sensitivity of 4.66 ± 0.03 pm/με. The two sensing structures were subjected to temperature, presenting low thermal cross-sensitivity.