A new scheme of aspherical microlense for efficient coupling high-power lasers to fibers

We propose and demonstrate a new scheme of aspherical microlens (ASM) employing a single-step grinding technique with fully automated process for efficient coupling between the high-power 980-nm laser diodes and single mode fibers. The grinded fiber endface exhibited a double-variable curvature in the major axis, and was clearly observed for both major and minor axes after slight fusion polish. The perfect aspherical shape of the ASM resulted in less grinding offset of 0.2 μm and better curvature radii control that led to high average coupling efficiency of 83 %. The result clearly demonstrated that the performance of the ASM exhibited high average coupling efficiency better than any other grinding techniques to form asymmetric microlenses.