Separation of Lamb waves modes using remotely bonded seven-core fiber Bragg grating Fabry-Pérot interferometer

This paper presents the use of a seven-core optical fiber with FBGs written into each core for the unique identification of symmetric vs. antisymmetric Lamb waves traveling in a structure. The Lamb waves are converted into longitudinal and flexural modes that propagate along the optical fiber. An experimental demonstration of the technique is presented and the Lamb waves are also independently measured using a 3D micro-laser Doppler vibrometer for validation.