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Broadband By Laser: Promises, Promises
Digital Quartz writes: "There's all manner of ways to get last-mile broadband access these days, from cable to DSL to microwave, but QuantumBeam, a Cambridge based company, wants you to surf by laser. Check out the article at The Wall Street Journal. I wonder how well it performs in the rain?" The promise of optical wireless is alluring, but it's also been said before ... I hope it actually pans out before it becomes old tech.
I guess this means that if I try to check the weather online in the morning and I can't get through, it's already gotten bad.
Kurdt
Kurdt
I'm not anti-social. Just pro-technology.
I'm afraid that's not quite to the point...
In fact, electrical impulses propagate down the wire at a speed much faster then the motion of the electrons themselves (which as you say, is around 1 to 2 m/sec). Depending on the medium, electrical impulses typically propagate at 10-90% of the speed of light, I think (I don't have figures handy).
This is because what I'm calling an electrical impulse is essentially a ripple in an electro-magnetic field: also known as a photon.
Consider transatlantic, for example. About 5000km, which is 5 million meters. At light-speed, that would take about 17ms. In fact, my ping time to US sites can be as low as 70ms -- so my internet conenction already has 50% lightspeed latency.
In fact, latency is more-or-less orthogonal to bandwidth anyhow (compare bps and baud, not that anyone gets those terms correct anyhow).
Jules
-- Any sufficiently advanced technology is indistinguishable from a perl script.
Pardon me if I'm wrong, but I had this strange idea that lasers require a direct line of sight. Any bouncing, and they lose their coherency.
So.
How the hell is this going to solve the "last mile" problem? For consumers in fairly large metropolises (any other takes on the plural?) there are too many bloody buildings in the way. Plus, the problem has already been solved with DSL, cable, etc. For consumers not in the last mile - well, the laser's going to max out at 5 kilometers, right? So those farmers still plodding along on a 28k are going to stay plodding.
I fail to see how this can be of any use at all.
Lucent have a division called Lucent Optical which are (unsurprisingly) world leaders at this sort of thing.
A good article about what they do can be found here
Incidentally, a company called Global Crossing plan to implement a network based upon lasers.
How will it affect surrounding wildlife to have lasers beamed through the air every which way? Will birds have to worry about being cooked as they fly?
Ok, risking to be troll I have to say, Read the fucking article!
-- "There are no fried pigeons or blinded pedestrians," Mr. Redgrave asserts.
The lasers are limited to 100 milliwats, compared to up to 500 milliwats used by the military, and have been deemed eye-safe."You can do more damage by looking directly at the sun than by looking at one of these things," he says.
The lasers have to meet public safety standards for electro-magnetic fields and power level restrictions set by the European Commission. --
Oh, that's a shame. Living in London, I think it would be a great idea to crank the power up a wee bit, just enough to take out a pigeon. I guess that would give a whole new meaning to the old 'ping of death'
This tech has been around for several years now.
The only difference now is it's significantly cheaper than it used to be, so you can build redundant links in through different paths.
Laser works well, for lower bandwidth, RF works well, but in the end, both are more prone to outage than fiber/cable, so if you can build proper redundant/meshed networks, you can approach the same reliability.