Re: Laser optic's communications

A laser shot through a telescope to another telescope some distance
away to be picked up by a detector is certainly a way to communicate
optically. Communications through the vacuum of space using this
technique is very reliable.

What bandwidth?

Well one way to get high speeds is to have a TV picture transmitted to
a TV camera sort of
deal, and modulate each pixel in the image to send a data stream

http://www.fujitsu.com/global/news/pr/archives/month/2005/20050121-01.html


This is what fujitsu has done with its technology. 64 channels each at
10 Gb/s - is 640 Gb/s. Not too shabby.

But high speed semiconductor switches (not mirror based) can operate in
the 100 femtosecond range switch speeds.

http://www.spie.org/app/Publications/magazines/oerarchive/july/jul99/cover1.html

This means the switch rate is 10 Thz!! If a 1,000 x 1,000 element
array of these babies could be placed on a semiconductor and at the
focus of a telescope, and aimed at another telescope with a 1,000 x
1,000 element detector and each element was modulated at 10 THz, you
could communicate at the incredible speed of 10 quintillion hertz!
That's 1 trillion channels of 10 Mhz EACH! A network of satellites
could provide global wireless broadband to modest transmitter recievers
on the ground for about $1 per channel per year!!!

Not too shabby!

I described a detailed satellite setup that would achieve a more modest
5 billion channel versoin of this including microwave downlink - but it
got zapped for some reason.

C'est la vie.

esmartguy wrote:
Laser broad band fiber optic communications system think of using a
laser the same way as fiber optic cable but through the air I'm
thinking line of site let's move at light speed shell we think of it.
Say good by to cable TV and say hello to laser optic communications say
good by to cloudy days water and ice crystals are know match for a
laser come on now. I bet the federal government would love to get a
hold of this one.

.

Relevant Pages

  • Laser for adaptive optics sees (gives?) first light on the 200-inch
    ... Laser Points to the Future at Palomar ... laser beam out from the Hale Telescope and up into the night sky. ... fraction of sky available to the technique known as adaptive optics. ...
    (sci.astro.amateur)
  • Re: Comet deflection capability
    ... Since we know the wavelength of the laser, ... optimum reflectance at the given angle for the given wavelength. ... the laser along with the telescope. ... mirror with an optical bandgap material. ...
    (sci.geo.geology)
  • Re: Comet deflection capability
    ... Since we know the wavelength of the laser, ... optimum reflectance at the given angle for the given wavelength. ... the laser along with the telescope. ... mirror with an optical bandgap material. ...
    (sci.astro)
  • Laser Points to the Future at Palomar
    ... Laser Points to the Future at Palomar ... Telescope and up into the night sky. ... fraction of sky available to the technique known as adaptive optics. ...
    (sci.astro)
  • Re: Flash Blinded By Green Laser
    ... when using a pointer and using a telescope around others with pointers, ... at star parties - that it is unlikely (but still possible, ... even when a laser colimator was held by a ... look into the eyepiece of any telescope to see how bright a laser is. ...
    (sci.astro.amateur)