Understanding high-power fiber-optic laser beam delivery

Fiber-optic beam delivery is commonly used in industrial laser systems. This article examines the conditions for the optimal propagation of high power beams through optical fibers. Beam quality effects by step and gradient index fibers of different lengths are considered. The differences between the diverging beam from a fiber and the beam at focus and on the fiber face are illustrated. Estimates are provided of the worst-case beam quality to be expected from fibers. Guidelines are also provided for the selection of beam delivery components based on the limitations of the optical system and the tasks to be performed.