"T-shaped" fibre Bragg grating sensor geometry for strain based metrology

This paper describes a "T-shaped" dual fibre optic sensor arrangement with integrated strain amplification for strain sensing. The strain sensor elements are based on optical fibre Bragg gratings (FBG). The sensor structure includes a common mode rejection capability of temperature induced drift. This rejection scheme is also expected to compensate for a change in Bragg wavelength (XB) due to ionising radiation. The operation of this sensor structure is demonstrated in an atmospheric pressure sensor operating in the region of 800 to 1100 mbar.