Using Visible Light for Data Transfer

James Evans writes "Wired has an article about a New Zealand company which has developed a technology to transmit data at speeds up to 400Mbps up to 4km. They are working to have it more resistant to changes in weather, as well as increasing the distance. It has a number of advantages, including lack of federal regulation of the spectrum, as it is of course, visible light." In related terrestrial networking news, waytoomuchcoffee writes "Science Blog reports that the backbone for the World's Fastest Network is up and running. It's a fiber optic 40 gigabit per second connection between Chicago and LA. Teragrid is a project by the National Science Foundation designed to link up supercomputer centers."

Comments

Federal Regulation

[Anonymous Coward]

How long do you suppose the lack of federal regulation will last?

Re:Federal Regulation

[tanveer1979]

Forever
Reason?
People will use headlights for another 50 years...Lights will be integral part of cities... Unless they ban flashing of lights.... this cant be outlawed
Consider this, when you flash your lights to an oncoming vehical, you are conveying information, or atleast acknowleding its presense, the tech was already there, its the 400 MBPs that is wow!

But I wonder how robust or secure is this.... can an airplane with flashing lights bring down your server.....?

Re:Federal Regulation

[Anonymous Coward]

Of course this can be regulated: "Transmission of information across property lines by technical means must follow the following regulations: bla bla." Just like with WiFi you could simply avoid premature outcry by having strict rules but lax enforcement (as long as no big business gets hurt).

Re:Federal Regulation

[CyberDruid]

Consider this, when you flash your lights to an oncoming vehical, you are conveying information
Consider this, when you flash your tits to an oncoming vehicle, you are also conveying information.
Yet there are sometimes laws against it.

Re:Federal Regulation

[cyb97]

Not only illegal, but pretty dumb as the houses would have a different grounding and therefore the ethernet cable you've dropped between the houses could end up as the grounding for one of the houses (remember that part about current always taking the easiest route from HS?).
If you want to have your computer/network equipment fried, go ahead and drop what ever you like out the window.
To be on the safe side, drop wireless or optical out the window as optical cables doesn't transmit electricity...

Hmmmm....

[roomisigloomis]

So, I guess we can finally have mirrors that are mirrors? Excellent!!!

Visible light regulation

[quintessent]

Some places do have ordinances against light pollution. I wonder how this would fit in. Also, will it come with a warning, such as "Do not look at transmitter with remaining good eye"?

flashlight

[soul_hk]

they better be careful at 400mbps, they may break the switch on their flashlight.

http://hksoul.myftp.org/

Fiber Optics?

[CoolQ]

Doesn't this just sound like fiber optics without the fiber?
I seem to remember this being done a long time ago. I've got an electronics book with a schematic for a serial 28k transmitter using visible light.
--Quentin

Re:Fiber Optics?

[Max Romantschuk]

Doesn't this just sound like fiber optics without the fiber?

There is one critical difference: ease of installation. Installing a fiber optic line is really cumbersome, since it involves lots and lots of digging.

This could really be something for high speed communications infrastructures. Take cities: digging is hard, and radiowaves pletiful, even so much as to people being afraid of them.

Pigeons could be a problem though ;)

Re:Fiber Optics?

[fredrikj]

Pigeons could be a problem though ;)

Not if you use sufficiently powerful lasers >:)

Red Light Destrict

[Chokma]

The LED-color should be chosen according to the content transferred... users sharing pr0n via P2P could build their own red-light-destrict! --- I wonder if powerful LEDs will attract insects and such - the connection speed could be reduced drastically by bugs.

Re:is anyone else thinking...

[Bluesman]

I was thinking that we'll have really fast semaphore flags next.

The problem is really tired arms.

Yeah, but more like ultra high speed morse code

[Cappy Red]

Except with morse code, I believe, you have to find the right frequency. Not much of a problem, but likely harder to find than a little light strobing across the street. Then there's the rather obvious quote from the article

On the other hand, bad weather, or anything that might block the light's path, can cause slowdowns or power failures.

"File transfer failed: Code 75(flock of seagulls)"

*honk*

Similar stuff...

[Zapper]

also check out Ronja.

Ronja (Reasonable Optical Near Joint Access) is an Open-Source project of optical point-to-point data link. The design is released under the GNU Public License: you get all the necessary documentation and construction guides free.

It works at 10Mb at up to 1Km.

(here here)...Re:already available and widely used

[the_pooh_experience]

It I am not sure how this is article bestows very interesting or novel information. Granted, the article mentions the wavelengths used are "visible", and "red". My guess is that they are emitting somewhere between 600 and 800 nm (typical visibly range is from 400 nm (purpleish) to 700 nm (red) however this is not a strict cut off, and if bright enough, even above 830 nm is visiblish).

Most telecom takes place at about 1550 nm, well into the infrared, but this is primarily because the typical fiber has nice properties in this range (absorption and dispersion). Therefore I am not sure there is much fundamental difference between infrared light telecom and visible telecom. Indeed they use very similar laser material (GaAs-based or InP-based diodes), are modulated the same way, etc.

Possibly this is neat because it is free-space optical stuff. However this (as pointed out previously) is not new. There are companies that are in place as we speek. Maybe deregulation may be of interest, but if the light it kept at the same wavelength as in fiber, then there is no need for an electronic klugey transceiver (detect the light in the fiber at 1550nm and drive a laser to re-emit the same signal at 6xx nm). Instead, an add-drop filter could be slapped on to the end, pick off the right wavelength, and feed that to a fiber which could be collimated as the source. This collimated beam then could travel over kilometers with no trouble. An all optical solution has a much

just a thought

400Mb? 1 Gb is old news.

[subreality]

Free air optical networking isn't really a new idea. Infrared units are pretty common. I'm not sure what supposed advantage using visible light has over infrared... IR isn't regulated (at least in the US, I can't imagine that it would be anywhere).

I investigated this for networking a couple of buildings my company had near together. Pretty cool stuff. You could get a gigabit connection over a few km of thin air. Cheaper units did 155Mb and for dirt cheap you could get 10Mb. Short range units used LEDs. Longer range ones used lasers.

I've been wondering why consumer ISP's haven't taken to this yet. It's a great last mile solution.

--Keepiru
--slashsuckATvegaDOTfurDOTcom