Cost effective refractive index sensor based on optical fiber micro cavities produced by the catastrophic fuse effect

•Recycling of optical fibers destroyed by the catastrophic fuse effect as refractive index sensor.•Low cost solution with a broad refractive index range of operation.•Sensor resolution of 3 × 10−4 RIU.

We propose a refractive index optical fiber sensor based on the micro cavities generated through the fiber catastrophic fuse effect. This sensor was tested in the measurement of solutions with refractive indices ranging from 1.3320 to 1.4280. The linear dependence of the reflection spectra modulation period as function of the surrounding environment refractive index leads to a resolution of 3 × 10−4 RIU. The proposed sensor is an innovative solution based on optical fiber damaged by the fuse effect, resulting in a cost effective solution.