Enhanced sensitivity high temperature optical fiber FPI sensor created with the catastrophic fuse effect

In this work, we describe a novel and cost effective approach based on optical fiber microcavities, for sensing high temperature values (up to 1150°C). The proposed sensor is produced by splicing standard single mode optical fibers with fibers destroyed by the catastrophic fuse effect, resulting in a microcavity structure in the fiber core region. These microcavities have a thermal sensitivity of 10.43±0.15 pm °C^-1, for temperatures up to 1150°C, which compares well with the sensitivity of Fabry-Perot interferometric sensing cavities but with the advantage of substantially reduced manufacturing costs.