Multipoint fiber-optic laser–ultrasound generation along a fiber based on the core-offset splicing of fibers

Fiber-optic laser–ultrasound generation is being used in an increasing number of applications, including medical diagnosis, material characterization, and structural health monitoring. However, most currently used fiber-optic ultrasonic transducers allow effective ultrasound generation at only a single location, namely, at the fiber tip, although there have been a few limited proposals for achieving multipoint ultrasound generation along the length of a fiber. Here we present a novel fiber-optic ultrasound transducer that uses the core-offset splicing of fibers to effectively generate ultrasound at multiple locations along the fiber. The proposed laser–ultrasonic transducer can produce a balancedstrength signal between ultrasonic generation points by reasonably controlling the offsets of the fibers. The proposed transducer has other outstanding characteristics, including simple fabrication and low cost.