Laser-aided manufacturing of ultra-high-aspect ratio optical fibers

The current landscape of optical fiber technology is dominated by fibers with a circular cross-section with axial symmetry and a centrally positioned waveguiding core. This typical layout is dictated by traditional manufacturing routes that often utilize furnaces, gas burners, and glass lathes. Contrastingly, in our work, we utilize laser-based glass additive-manufacturing to melt, weld, and reshape glass powders and prefabricates to create fiber preforms. Additionally, through a combination of mid-IR CO₂ laser melting and oxide nano-powder jets aimed into laser-induced hot-zone, high quality glass features can be 3D-printed onto the fiber preform. In our work we focus on high-aspect ratio preforms that can be then drawn in traditional draw towers into over 100 m long ultra-thin fibers. Here, flat fibers as thin as 35 µm and aspect-ratio of up to 27:1 with sub-µm surface flatness were made. Furthermore, by utilizing this novel print-stack-draw approach, microstructure and chemically doped features for e.g., waveguiding and optical gain can be spatially tailored, both laterally and along the direction of draw. Compatibility of these fibers with standard counterparts such as commercial single-mode-fibers was demonstrated through e.g., laser-based splicing. The new manufacturing approach utilized in this work unlocks highly flexible, novel photonic designs with large disruptive potential for areas including lab-in-fiber, physical sensors and fiber lasers.