Little of the Present Day &
Fibers, Optical Recording, and the ultimate, Optical Computing
transport using Soliton
Pulses in Dispersion-Shifted Fiber
Fiber: Errorless data transmission: 50 Gb/s, at over 19,000
km, No Repeaters
Optic Cable: TAT-14 (map)
cable, which incorporates dense wave division multiplexing (DWDM)
with 16 wavelengths of STM-64 per fiber pair, will operate at a protected
capacity of 640Gbps, with a total capacity of 1.3 Tbps; enough to
transmit the content of more than 400 full length movie DVD disks every
second: that is 1 DVD for every man, woman, and child on earth in less
than 6 months.
that amplify light using
Erbium-doped Fiber Light Amplifier EDFA
40 THz bandwidth (12.56
Fsec pulses from Erbium-doped Fiber LASER
Pulse widths ~ 10 Femtoseconds (10
Light travels 1/8th the thickness
of a sheet of paper.
10 Fsec is to one second as one
second is to 3.2 million years.
next generation of computing--Optical Computing, will have CPU operations
and bus speeds measured in THz, data paths >>1024 bytes wide. Logic operations
will occur in ‘optical space’ as Soliton wave packets interact algebraically--the
operations happen outside of silicon. The hardware: sub-micron LASERS communicating
across sub-micron space, both transferring and processing data, stored
in Terra-Byte optical storage. [*]
There is a relatively new fiber optic
data transmission scheme that utilizes something called Soliton Pulses.
These are very short bursts of light generated in an Erbium-doped Fiber
LASER. Soliton light can be used to transmit data at rates in excess of
50 Gb/s, at distances over 19,000 km of Dispersion-Shifted Fiber, requiring
no repeaters, and with no errors. This data rate is the equivalent of sending
6,200 bibles per second. At this rate, one bible could be sent to everyone
9 people--in about 10 days.
In the case of repeaters, in a long-haul
fiber: instead of converting the light into electrical signals, amplifying,
correcting errors, retiming and retransmitting light pulses for the next
20 km span, an optical amplifier is used. It consists of about 30 meters
of Erbium-doped fiber, assorted filters and beam splitters, and pumped
by a 15 mW LASER diode operating at 1550 nm. This arrangement adds about
30 dB of gain with no appreciable noise. Also, the bandwidth of this amplifier
is on the order of 40 THz. At this rate, one bible could be sent to everyone
on earth, 5.5 9 people, in about 18 minutes.
The Shortest LASER pulse,
to date, is ~10 Femtoseconds (10 -15 sec). Light would travel
1/8th the thickness of a sheet of paper in that time.
1 Fsec is to one second as one second
is to 32 million years.
the future of technology is a Fool's Errand.