This text refers to items from 27 to 31.
Under our feet, cables carry data between our homes,
offices and data centers at a pace that can match the speed of light.
The data travels as light that runs through strings made of materials
like glass and plastic.
Researchers at the University of Maryland want to do away
with the cable altogether and just use air to guide the light. That's
not as simple as it sounds, because a laser sent through air will
spread apart and interact with particles, gradually losing its intensity
over time.
The research team instead caused patches of air to mimic
a fiber optic cable by creating tubes of dense air surrounded by
low–density air. In a fiber optic cable, a laser travels through a
string of glass. When it tries to leave the glass, it hits a wall that
reflects it back into the center, guiding it along the length of the
cable. The cable made of air works in the same way.
“It's like you could just take a physical optical fiber and
unreel it at the speed of light, put it next to this thing that you want
to measure remotely, and then have the signal come all the way
back to where you are," University of Maryland team lead Howard
Milchberg said in a release.
Signals that traveled through the air cable were 1.5 times
stronger than when they were sent through plain air. The team was
able to send them over a distance of three feet and is now interested
in pushing the range to 150 feet.
If the University of Maryland team succeeds, the air cables
could be used for communication in remote locations on Earth
where laying fiber optic cables is extremely difficult, or places
where it actually is impossible like space. NASA is already
experimenting with laser communication between the International
Space Station and Earth. The technique could also be used to probe
the Earth to make topographic maps or examine the chemicals
present in hard–to–reach places like the atmosphere or a nuclear
plant.
S. Brewster. Making optical cables out of air could boost
communication in space. Internet:
According to the text, air cables
rely on differences of air density.
