WHAT THE RESEARCH IS:
An alternative to copper conductor for submarine cables — and the first major development in cable technology since the early 1990s. Facebook researchers have partnered with Alcatel Submarine Networks to develop the first aluminum conductor for submarine cable systems.
HOW IT WORKS:
In the past 10 years, fiber-optic cable capacity has grown from 5 gigabits per fiber pair (FP) to more than 20 terabits per FP. We are rapidly approaching the per FP Shannon limit (the theoretical maximum capacity that can be transported by an optical fiber). Work has been done to increase the bandwidth per optical core — the task now is to increase the total number of optical cores. In other words, we need a way to increase the number of FPs per cable.
As a conductor, aluminum allows for a much lower cable voltage drop, which allows for a higher number of FPs per cable. That makes aluminum a solid option to increase the number of FPs per cable — that’s also significantly less expensive than copper.
WHY IT MATTERS:
These systems with a large number of optical fibers are an important first step toward space-division multiplexing systems, which could help increase the capacity of cables in the future.
