Transversely loaded fibre Bragg grating for pressure measurements

Abstract

A fibre Bragg grating (FBG) pressure sensor, based upon the transverse loading of half its length, is proposed and demonstrated. When a transverse load is applied to half of the length of an FBG, a second Bragg peak is generated in the reflection spectrum, which separates from the initial Bragg peak. The new peak exhibits a red shift in wavelength as the load is increased. A new data analysis technique, which improves the minimum detectable pressure is discussed. A normalised pressure sensitivity of 5.73x10 -3 ± 5.23x10 -5 MPa -1 was obtained. The technique offers the opportunity to measure independently pressure and temperature using a single FBG sensor element.