Theoretical Lifespan: 30 to 50 Years. In a perfect vacuum, the silica glass (SiO2) core does not degrade. Manufacturers like Wolontek design cables to remain within attenuation specs for this period. When you invest millions in a fiber optic cable network, you are buying a long-term asset. " The reality is more nuanced: silica The optical core is virtually chemically indestructible, but the sheaths, coatings, and. The lifespan of fiber optic cables can significantly impact the efficiency and reliability of our internet connections. A process called 'stress corrosion' is the biggest threat to the longevity of fibre cabling.