In‐Fibre Grating Techniques for Strain Sensing

: The principles of fibre optic strain sensing based on the use of in-fibre Bragg gratings are presented with emphasis on advances in the grating inscription technology. Multiplexed array techniques for structural health monitoring are described with reference to modern industrial applications. Recently established techniques for improving the multiplex density, for extreme strain monitoring, and for high sensitivity measurements using long period gratings are addressed.