This paper presents a real-time monitoring system for high-voltage direct current (HVDC) submarine optical cables using distributed acoustic sensing (DAS) technology. Fiber-optic cables are the backbone of modern connectivity—powering 5G networks, global internet backbones, and data center interconnections with near-light-speed data transmission. While these cables are engineered for durability (with some rated to last 25+ years), they are not invulnerable. Even. This article introduces case studies of failures that have occurred in optical fiber cables as well as some countermeasures against such failures. Cable, fibre optic cables, data transfer, data loss, functional criterium, damage criteria, bend diameter, temperature, fire conditions, heat flux, cone calorimeter, probabilistic distribution, risk analysis. 0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly. In August of 1999, Boeing Corporation (Boeing) engineers being used on International Space Station flight a defect in the glass fiber (see Figure 1, “Rocket and NASA engineers and managers, Boeing created and reliability of the cable installed in the U. Technologies and Radiation Effects.