Axial strain based Bragg grating level sensor

Abstract

Design and construction of a liquid level sensor using FBG, based on change in axial strain due buoyancy is presented. The lever in the system induces axial strain on the FBG due to change in level, resulting in modulation of the Bragg wavelength. The shift in the Bragg wavelength is a measure of change in liquid level. The Bragg grating (3 mm length) used in this work has been fabricated using a phase mask technique and written in a photosensitive optical fiber. A sensitivity of 0.106 nm/cm is observed for a level change of 13 cm. The results obtained indicate that the sensor has good sensitivity and repeatability. The sensor can be customized for a required level measurement for a particular application.