I understand the physics behind how the cables themselves work in transmitting light. What I don’t quite understand is how it’s possible to convert millions of messages, emails, etc every second and transmit them back and forth using only a few of those transoceanic cables. Basically, how do they funnel down all that data into several cables?
In: Engineering
A key feature of fiber optics is the ability to multiplex multiple wavelengths of light onto the same strand of glass. Think of it like a prism- the one beam of white light can be broken down into multiple beams of colored light. Each of those “colors” (the light used in fiber operates at wavelengths invisible to humans) can carry as much data as your modulation scheme allows for- say 1Gbps to make it easy.
Using dense wavelength division multiplexing (DWDM) we can fit 80 of those wavelengths onto one strand. And of course most fiber cables are multiple strands- lets say its a small cable with only 12. Doing the math, that’s almost 1Tbps of bandwidth on a fiber cable.
Real life applications can carry even more, it all depends on the equipment being used. As our technology improves we’ll be able to modulate more data per wavelength and pack more wavelengths per strand.
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