Multichannel fiber-optic interferometric sensor for measurements of temperature and vibrations in composite materials

A multichannel fiber-optic interferometric sensor for measuring temperature and vibrations in composite materials is presented. The fiber-optic sensor is designed for simultaneous monitoring of all channels with optical fibers embedded in the structure. The multichannel arrangement with a common reference path and the transducer principle, based in optical phase measurements, provide a high sensitivity sensing of two parameters, their spatial distributions, and the rules of calibration. Our results show that the temperature gradient and the propagation of vibrations along a carbon fiber board are obtained at the same time using the proposed technique as well as their dynamic behavior.