https://www.electricaltechnology.org/2018/02/submarine-cable...
Fiber theoretically has unlimited bandwidth. The bandwidth of these cable system is limited by the transmission gear used to light the fiber. This is the same for all optical telecom gear though. The cables themselves have a lifespan though. Newer systems have a lifespan of around 25 years.
The cables themselves have a lifespan, but it's far longer than 25 years. Many cable systems have had their lifespan extended beyond 25 years, but is more of a question whether they are economically viable, rather than technically viable.
A lot of cable systems have been retired, purely because they had become obsolete and a new system was more cost effective.
Fiber optics cables themselves are very longlived, if there is no external trauma. There are cables from the 1980s still in use. It's more likely that the amps in a subsea system fail long before the cable. Once the amps start failing, it usually isn't cost effective to keep using the cable system anymore.
Literally the last sentence of my post is "Newer systems have a lifespan of around 25 years." What is your point?
>"The cables themselves have a lifespan, but it's far longer than 25 years."
No this is incorrect. There are a many factors that limit the lifetime of "wet plant" - chief among them are fiber hydrogen exposure, which causes attenuation. There is also glue and insulation aging as well as corrosion. And "the cable" in submarines systems always includes all of the passive optical components, alignments, joints and passive electronic components. Extending these system is generally on the order of 5 years. That could hardly be classified as "far longer than 25 years."
Cable system lifespan != cable lifespan
> No this is incorrect.
How do you then explain subsea cables that have been in operation since 1989? Facts don't care about your opinions.
Not that I disagree with the listed factors that limit the lifetime of the wet plant. 25 years is a design target, not a hard limit.