How Can Light, Plus Glass, Equal The Internet?


[MUSIC PLAYING] NAT: Hey, there. Welcome back to “Nat & Lo.” I am Nat. And you may notice that
Lo is not with me today. But that’s because she is
climbing mountains in Colombia. I will insert this
picture into the video now so you can be very
jealous along with me. Moving on, a couple of months
ago, we got to go aboard a ship and tour a factory to see how
underwater internet cables are made and installed at
the bottom of the ocean. We learned how these cables
use tiny fiber-optic strands the size of a hair to send your
photos, videos, and web pages. VIJAY: As little pulses
of light over which you impose your
digital information. [CRICKETS CHIRPING] NAT: Does this look
like the face of someone who fully understands
what they’ve just heard? Something that takes years of
studying to truly comprehend– pulses of light? I kept wondering, what’s
really going on here? I wanted to know, how do
fiber optics actually work? So I did some more research,
double-checked everything with Vijay, our
friend at Google, who’s a fiber optics expert. And in this video, I’m going
to try to answer the question, how can light plus glass
equal the internet? Light is an accurate but
also somewhat misleading word when it comes
to fiber optics just because it makes us
think of the light we know best, which is visible light. But this light is just
this small handful of wavelengths on the full
electromagnetic spectrum, all of which x-rays, microwaves,
radio waves, even Wi-Fi waves are technically light. The light that zooms through
these fiber-optic cables are infrared wavelengths–
invisible to our eyes, but for the sake of
this video, represented by these little light blobs. What also makes
this light different is that it’s made by
Light Amplification by Stimulated
Emission of Radiation, or in other words, a LASER. But this isn’t your average
laser pointer or techno dance party laser. The beam it produces
is extremely narrow and directed, meaning
even though the laser itself is only the size
of a grain of salt, its beam is powerful
enough to blind you. So for these reasons
and many others, it travels through
protected glass tubes, more pure than any
glass you’ve ever seen. For example, if you were on a
boat and the water below you was as clear as
optical fiberglass, you would be able
to see miles down to the bottom of the ocean,
just because any little piece of dust or other impurity
could disrupt this light from traveling through it. What’s amazing to me is that
when I look at this glass, it looks like just
one little piece. But really, it’s made
up of several parts. There’s a glass core
surrounded by a glass cladding, and then you have a plastic
buffer to protect it. So depending on what
type of fiber it is– is it going thousands of miles
under the bottom of the ocean, a few hundred miles on land,
maybe just a few hundred feet– all this affects how big
the various parts are and how the light
travels through it. For example, let’s say someone
comments “FIRST” on this video. And I guarantee you someone will
comment “FIRST” on this video just because I said that. That comment starts off
as electronic 1’s and 0’s. So to translate
those into light, if the fiber is just
a few miles long, a laser pulse is on and off,
on and off 10 billion times a second, an on equaling a
1 and an off equaling a 0. And these light 1’s and 0’s
then race through the core, bouncing off the cladding,
zigzagging their way through to be,
literally, “FIRST.” But for these underwater
internet cables, the light has to go
really long distances, so it’s a bit more complicated. The laser is actually
left on the entire time. And then an external
device, a phase modulator, adjusts it 100 to 200
billion times a second. And it doesn’t bounce
around because the core it’s traveling through is only
the size of a red blood cell, making it essentially
a straight shot. But here’s the thing. It’s actually far
more complicated than even this description. To see what I mean, we need to
strap on our infrared goggles and slow things down a bit. You see, each glass
strand can actually handle not just one, but 100,
different infrared wavelengths traveling through
it at the same time, meaning it’s not just one
highway with one lane. It’s like a highway
with 100 lanes with bumper-to-bumper
traffic whizzing by at 450 million
miles per hour. And that’s not even
all because right now, researchers are
developing new techniques to make fibers with not just
one core, but seven, meaning that’s like seven highways,
all with 100 lanes, all inside one tiny
little piece of glass. So while the internet is still
a massive physical network with large infrastructure,
computers, and data centers, and ships installing heavy
steel-wrapped cables, the more I kept
zooming in, the more I realized how the real
massiveness of the internet is at the microscopic level, the
level beyond human perception. Just touch some of
your hairs right now and realize something
that small– that’s all it takes
to send anything you want to anybody in the world. Thanks for watching. And if you have
any more questions about how fiber optics
work, leave a comment below. And Vijay has agreed
to answer them. [MUSIC PLAYING]

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