Distributed strain and curvature measurements based on tailored draw tower gratings

Abstract

Measuring strain in an unobtrusive and distributed way is of key importance to many avionics applications. Optical sensing technologies based on fiber Bragg gratings (FBGs) enable multiplexed strain measurements while offering precise location tracking. These precise and multiplexed strain measurements are enabling monitoring of more advanced parameters such as curvature and shape [1,2]. We are introducing a unique combination of two trends within the field of FBG sensing. The first trend capitalizes on using a Draw Tower Grating (DTG®) process to inscribe FBG configurations enabling quasi-continuous arrays of fiber Bragg gratings. Secondly, we exploit the ability to accommodate several independent optical fiber cores within a sensing structure, either within the same optical fiber, designated as MultiCore Fiber (MCF), or closely bundling similar optical fibers, designated as MultiFiber Bundle (MFB). Both configurations, each with its own merits and limitations, enable distributed curvature measurements based on differential strain measurements using FBG technology.