The technology has even more headroom. Based on the efficiency of the line, Facebook and Nokia believe they can ramp it up to 32Tbps per fiber in the long run.

It's likely going to be a while before you see these kinds of upgrades arrive in earnest, although the test runs show that it can hold up in real conditions. Whenever it does, though, the practical implications are far-reaching. The upgrade could help these fiber line operators keep up with ever-increasing internet demands without having to rip up or add to their existing lines. It could also make undersea fiber more practical by lowering the cost of bandwidth -- you could see lines that weren't viable before.