Long fiber Bragg gratings for liquid level sensing

Autores UPV
CONGRESO Long fiber Bragg gratings for liquid level sensing


The study, design and performance evaluation of fiber Bragg grating (FBG)-based photonic sensors to the aim of realizing devices for discriminating both liquid level and temperature changes are proposed and experimentally performed. The analysis carried out is based on a 10 cm-long uniform FBG specially designed for this particular aim. Two different techniques have been implemented. The first scheme presents a time-frequency analysis by using a short optical pulse. Here, the back-reflected signal has been monitored and a 2 mm spatial resolution is achieved, determined by half the incident pulse duration. Second, a technique based on microwave photonics (MWP) filters has been demonstrated, too. Here, a spatial accuracy under 0.5 mm is obtained using a modulator and a photo-detector with a modest bandwidth of less than 1 GHz. Furthermore, in both configurations the temperature of the liquid is detected.