Spatial beam properties of combined lasers' delivery fibers

The superiority of parabolic-index fibers over step-index fibers in delivering high-beam-quality light out of incoherently combined lasers is demonstrated numerically and experimentally. By utilizing the tapered fused bundle-combining approach and connecting it with delivery fiber, we point to an efficient, rugged, all-glass, integrated, and nearly brightness-preserving device that is capable of transmitting high-quality output beams.