Self-referred microcavity-based fused-fiber fabry-perot refractometer

•Recycling fused optical fiber to develop a miniature self-referred Fabry-Perot microcavity sensor.•The physical theory and Finite Element Method (FEM) of the Fabry-Perot microcavity were considered to fabricate an efficient sensor.•This sensor simultaneously measurements the refractive index and temperature.•This sensor has the advantages of low cost, high repeatability, and small dimension, making it a desirable sensor for chemical and biomedical applications.