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Researchers have found a way to make glass tubes a tenth the thickness of your hair send
cat videos around the world.
Better.
They found a way to do all that but better.
HI!
Julian here for DNews.
Your smartphone is super cool, you’ve got all the DNews you could possibly want, anywhere.
But you’re not really totally wireless.
You’re within a few miles of a cell phone tower, but the tower may be hundreds of miles
from the servers where all that juicy knowledge is stored.
So how do you connect the two?
Why with laser beams, of course!
Let’s begin at the beginning, which is all the way back in the 1840’s when Swiss Physicist
Daniel Colladon noticed he could shine a light in one end of a water pipe and it would come
out the other side.
170 years later, modern optic fibers are basically the same thing, but they use optically pure
glass and are 9 thousandths of a millimeter thick instead.
You may be wondering, how does light travel inside water or glass without just bouncing
out and being lost?
The answer is it all has to do with the angle the light is shone in.
If the light is hitting the walls of the glass at a shallow angle, less than 42 degrees,
it’ll experience total internal reflection and bounce back and forth down the glass.
This property of light is the same reason you can look out over a lake and see a beautiful
reflection, but when you look straight down you can see into the water.
To make sure none of that light does leak out, the optical glass is encased in a cladding
with a higher refraction index that can bend light back into the glass, then that’s put
in a buffer coating.
Each one of these fibers can carry the equivalent data of 10 million phone calls, and hundreds
of thousands are bundled together and stuffed in a jacket to make a fiber optic cable.
Because of them you can send a beam of light to the other side of the planet in a seventh
of a second.
Being able to shoot light through a glass tube to China is all well and good, but you
still need a way to send information, and that’s where modulation comes in.
Modulation is when you vary some property of a wave to encode information.
Then when it gets to the destination, it’s demodulated to separate the carrier from the
message.
You’ve been dealing with it a lot and you might not even know it.
FM radio uses frequency modulation, which is when a wave’s length is altered.
AM is when a wave’s Amplitude is changed.
and the Modem in your house is short for Modulator Demodulator.
In fiber optics there are a lot of ways to modulate the beam and send information.
There’s AM, Sine wave FM, Square wave FM, pulse frequency modulation, which is basically
turning the beam on and off so it can be interpreted as ones and zeroes.
All of these methods need costly external modulators, which are costly and inefficient.
But Dr. Radan Slavik, who is a research fellow at the Optoelectronic Research Centre and
probable Jame Bond nemesis, has improved another method.
They’ve devised a way of adjusting the current of the laser beams so they can have better
control of the optical field and send more information.
Actually the words Dr. Radan Slavik used were, “Exquisite control… over the optical field
generated directly from a current-modulated semiconductor laser.”
Tell me he’s not a Bond villain!
There was another awesome breakthrough in sending wireless signals a few months ago.
I talk about that and a bit more about Fiber Optics over here.
If you know of some interesting tech in the pipeline and want us to cover it, let us know
in the comments and I’ll see you next time on DNews.