how do undersea cables transfer data from and to millions of people simultaneously?

Question

I understand it’s just signals and 1s and 0s but don’t the signals overlap in the undersea cables?

In: Engineering

Answer 1

An undersea cable contains anywhere from 8 to 24 individual fiber strands. Within each fiber strand the operator of the network uses DWDM or dense wavelength division mulltiplexing which is the concept of using multiple wavelengths of light to communicate multiple different networks on the same strand of fiber. When you combine that with multiple strands of fiber you have very good scaling capabilities. For example, you could deploy 24 strands of fiber with 30 wavelengths of light on each fiber being multiplexed together to deliver 720 completely different networks which themselves are being multiplexed as Ethernet packets.