Sistema eletrônico para medição de temperatura em fibra óptica utilizando grade de Bragg

Abstract

The acquisition and monitoring of physical quantities pertains to an important role in engineering. With it you can control processes, as well as guarantee the equipment’s adequate functioning and it’s safety. These quantities are monitored from sensors which can be utilized under given conditions. However, in some applications, like temperature monitoring in power transformers, it is required electromagnetic interference immune sensors. In this context, the usage of optical sensors are adequate given their passive behavior (no power supply required). This paper proposes an alternate method of interrogation (signal acquisition) to temperature reading using fiber Bragg gratings (FBG) in optical fiber networks, which can be used as sensors due to it’s spectral response when temperature or deforming variations occur. This method consists on varying the spectre of a laser under FBG’s reflection pattern and analyze the convolution signal reflected by the sensor. For this project, it was used: one control board which includes signal conditioning analog circuits to capture the detection of the reflected signal, one analog-digital converter, one digital-analog converter, one microcontroller programmed with the aforementioned method; and one board directed to the laser’s safety and activation. In addition, for testing purposes, the laser and the FBG were replaced by an electronic system which simulates these devices behavior, eliminating direct risks to the optic equipment’s integrity.With the project’s result, the system’s implementation with the laser and the FBG can be assembled with a higher device security.