Fiber-tip polymer filled probe for high-sensitivity temperature sensing and polymer refractometers.

A compact and robust Fabry-Perot interferometer (FPI) based on polymer core is proposed and experimentally demonstrated. The fabrication is low-cost and has simple processes, including fusion splicing and polymer injection. Its characteristic is that the polymer fills the entire capillary core, which is easy to demodulate, and provides a good platform for the refractive index measurement of the polymer after curing. The experimental result shows a linear temperature sensitivity of 1226.64 pm/°C between 39°C and 54°C. Furthermore, we also used the Vernier effect to improve the temperature sensitivity as high as -15.617 nm/°C. The proposed FPI structure provides potential application in the research of sensors and polymer optical fibers.