[Laser] 144km 10 Mbit/sec laser link acheived

[John E. Matz]

Might be, but not for amateurs, since it was not done by hams, but by a 
commercial-type organization.  Very impressive though.
John Matz KB9II
----- Original Message ----- 
From: "Ed" <bernies at netaxs.com>
To: <laser at mailman.qth.net>
Sent: Thursday, November 08, 2007 4:31 PM
Subject: [Laser] 144km 10 Mbit/sec laser link acheived


> is this a new terrestrial record?
>
> -ed
>
>
> http://www.oerlikon.com/ecomaXL/index.php?site=SPACE_EN_press_releases_detail&udtx_id=5060
>
> Oerlikon Space demonstrates laser data link across a distance of 1.5 
> million kilometres
>
> 07 Nov 2007
>
> November 2007 - On the Canary Islands last week, a team from Oerlikon 
> Space
> demonstrated the feasibility of a laser link across a distance of 1.5
> million kilometres for the first time ever. In the future, laser links 
> like
> this one will be able to transmit data across huge distances through the
> universe far more rapidly and efficiently than is possible using
> conventional radio links today.
>
> To prove that data transmission across the vast distance of 1.5 million
> kilometres is really feasible, the Oerlikon engineers had devised a 
> special
> experiment in which they set up a laser link between the islands of La 
> Palma
> and Tenerife. The transmission unit was modified in such a way that the
> conditions on the 144-kilometre stretch between the islands exactly
> reflected those that would prevail on a 1.5 million kilometre link through
> space. This was achieved primarily by reducing the emission aperture of 
> the
> laser to a diameter of less than half a millimetre in order to weaken the
> light signal.
>
> The Oerlikon team installed the transmission unit in a container beside 
> the
> Nordic Optical Telescope at an altitude of 2400 metres on Roque de los
> Muchachos, the highest mountain on La Palma in the Canary Islands. Because
> of the unusually clear air, this is an ideal location for optical
> experiments. The receiver terminal was situated in the Optical Ground
> Station (OGS) of the European Space Agency ESA on Tenerife.
>
> Although the optical experiment was hampered by unfavourable weather
> conditions with unusually high cloud and strong winds during the first few
> days, a breakthrough was achieved at noon on Wednesday. The experts from
> Oerlikon Space succeeded in establishing a laser link between La Palma and
> Tenerife. In the course of the experiment, they achieved transmission 
> rates
> of over 10 Mbit/sec. At this speed, it would take a mere two seconds to
> transmit the entire text of the Bible. The data rate would also be
> sufficient to transmit three digital television programmes simultaneously.
>
> Laser-based data transmission has several advantages over conventional 
> radio
> links. Because of the shorter wavelength, lasers can transmit more data 
> than
> radio signals in the same period of time. Lasers can also be far more
> accurately aligned with the receiver than radio waves, and therefore 
> require
> less power for data transmission.
>
> These advantages are particularly useful in space applications, for 
> instance
> when large quantities of data need to be transmitted rapidly back and 
> forth
> between satellites. When data have to be transmitted across vast 
> distances,
> too, laser communication will be the medium of choice in future. The
> distance of 1.5 million kilometres that was simulated on the Canary 
> Islands
> is equivalent to the distance between the Earth and Lagrange points L1 and
> L2. These mark specific positions in space at which it is particularly
> advantageous to place space telescopes. Equipped with laser terminals,
> telescopes such as these will in future be able to transmit far greater
> quantities of observation data to Earth than is possible by radio today.
> Laser communication could also be used for transmitting data to Earth 
> during
> future missions to the moon.
>
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