Competence Center for Specialty Optical Fibers

ZBLAN, a heavy-metal fluoride glass fiber, achieves demonstrably better transmission in the mid-infrared range compared to silica fibers and is predicted to outperform their optical performance across the ultraviolet to mid-infrared spectrum; however, achieving this potential is hindered by crystallization during terrestrial fabrication. In this study, we leverage the microgravity environment aboard the International Space Station (ISS) to explore conditions that enable high-fidelity fiber drawing with reduced optical loss. We produced ~12 km of ZBLAN fiber on the ISS, marking the first time sufficient space-drawn material is available for comprehensive characterization. An international consortium of 5 organizations evaluated ~2.1 km length of samples with highest diameter uniformity from the produced fibers. Comparative analyses reveal that space-drawn fibers with a step-index core-and-clad structure exhibit lower optical attenuation and enhanced mechanical performance relative to their ground-based counterparts. These results demonstrate that microgravity manufacturing enables high-performance ZBLAN fiber production for near- and mid-infrared applications while opening new opportunities for advanced photonic materials in space-based industry.