Bragg Fibre for Sensing Applications

摘要

In this work, we propose to take advantage of properties of a Bragg fibre for optical sensing. The Bragg fibre exhibits three concentric high refractive index layers embedded in pure silica and surrounding a 35μm diameter core. A short (0.3 m long) piece of Bragg fibre slightly multimode, is used to elaborate an intermodal interferometer, the spectral response of which exhibits a fringe pattern that depends on the operating wavelength, which can therefore be used as a sensor. The two modes considered were found to be the fundamental LP_(01) and the high-order mode LP_(02). The sensor has been characterized in strain and temperature and presents a sensitivity of- 1.09 pm/με and 14.1 pm/℃ respectively. The sensor demonstrated insensitivity to curvature thanks to well known Bragg fibre properties.