Fibre-optic Link Around the Globe (FLAG) is a 28,000-kilometre-long (17,398 mi; 15,119 nmi) fibre optic mostly- submarine communications cable that connects the United Kingdom, Japan, India, and many places in between. This updated list ranks the 20 largest fiber-optic cable companies worldwide and summarizes what each vendor is best known for—core product lines, regional strengths, and typical project fit. Use it as a fast shortlist when planning new FTTH/FTTA or data-center builds. Leaders like Corning, YOFC, Fujikura, and Prysmian drive innovation and scale the infrastructure behind the digital economy. The cable is operated by Global Cloud Xchange, a former subsidiary of RCOM. Core Products: Fiber optics, fiber optic cables and connectivity solutions Primary Markets: Europe, North America, South America, Asia Ongoing Projects: Expanding high-capacity submarine cable networks and 5G network infrastructure Reason for Top 20 Ranking: As the world's largest fiber optic cable. Based on 2025 rankings from industry sources like Owire and TSCables, the top manufacturers are evaluated on market share, innovation, and global reach. This list incorporates leading players, including Dekam-Fiber, Corning, Prysmian, and CommMesh, which stand out for their contributions to. Optical fibers are clear elastic cables made up of high-grade plastic, glass, and silica through which light signals can be transmitted with very little loss of strength.