Fiber optic sensor systems for ultrasonic NDE: state-of-the-art and future potential

A review is presented of the principles of both intrinsic and extrinsic fiber optic sensing systems and some of their applications to nondestructive evaluation (NDE), with special emphasis on current research demonstrating applications of fiber optics to ultrasonic NDE. Single- and multimode flexible optical-fiber elements, individually or in a variety of arrays, provide useful tools for many NDE applications ranging from directed photothermal excitation to remote sensing. Optical-fiber components have several important advantages. They are dielectric devices and thus are largely insensitive to electromagnetic interference. They can be readily adapted for use in harsh environments, and their dimensions and geometrical flexibility support compact, readily adaptable designs and facilitate access to remote or otherwise inaccessible locations