Ultracompact fiber sensor tip based on liquid polymer-filled Fabry-Perot cavity with high temperature sensitivity

An ultracompact liquid polymer-filled Fabry-Perot interferometer (FPI) with high temperature sensitivity was proposed. Two-photon polymerization technique was used to fabricate the liquid polymer-filled micro-structure on the end-face of optical fiber. The size of the micro-structure can be precisely controlled and the total length is only 20 μm. The polymer micro-structure combined with the single-mode fiber formed a liquid polymer-filled FPI, and the temperature sensitivity of the FPI can reach up to 877 pm/°C. In addition, the polymer material is of good biocompatibility. Therefore, the proposed FPI may find widespread application in biomedicine, industry, and environmental science due to its high sensitivity, biocompatibility, compactness, and good stability.