Using IR Lasers Instead of Fiber 209
Artifice_Eternity writes: "Can't deal with the trouble, time or expense of digging up the street to get fiberoptic cable to your building in the big city? There's another way...infrared line-of-sight infrared lasers between your building and another one nearby. Repeaters and redundancy can keep the chain going reliably for miles, with gigabit data transmission rates."
Wireless networks. (Score:1, Interesting)
And lets not forget how fragile the whole system would be. A mirror, heavy fog, lightening striking, etc. all come to mind. From what I've heard wireless repeaters attract lightening quite well, and a nice surge like a lightening bolt can bring makes a wireless network a little worthless.
Hopefully with all this new technology coming out, cheap wireless networks will be next on the list of things that are cool for geeks. I mean WHO DOESN'T have their own intranet in their house???
Re:Wireless networks. (Score:1)
Re:Wireless networks. (Score:2)
READ THE ARTICLE, PLEASE (Score:4, Insightful)
And note that even in my summary I mentioned redundancy -- multiple IR beams are designed to compensate for bad atmospheric conditions -- and each hop in the network is a short distance for the same reason.
I wish it worked that way... (Score:3, Informative)
1. During a good snow, it will not cross a street (200ft, +-10). (Commercial units. Had a demonstrable five mile range on a pretty day.
2. I don't know where you are located, but when it snows or rains here, it snows and rains pretty much all over the city (Anchorage, AK). Redundancy only works if a few of your transports get interrupted. Otherwise you get sit back and answer the user support line and make up excuses while watching the routes flap in the routing table.
3. Glass windows in many larger buildings are infrared mirrors. Heat loss reduction. Don't even think about the cost of changing one in a space-frame building. Equipment goes outside.
4. By the time we got "redundantised" and "routerised" to make the system even remotely reliable, paying the local one of the LECs for SONET transport was looking pretty good.
I might be tempted to use this where the sun shines a lot, or in large enclosed structures, or to some place completely inacessable by other means, but I don't think it's ready for prime time.
Re:READ THE ARTICLE, PLEASE (Score:1)
Re:We were thinking of selling these things but... (Score:1)
Re:Wireless networks. (Score:3, Informative)
Also, If you're clever you could use fiberoptic feed from a source indoors, and be COMPLETELY electrically isolated from the rooftop.
Also, last time I checked, my Grandfather of 92 doesn't have a LAN in his house. (What, from the fireplace to the kitchen?)
Re:Wireless networks. (Score:2, Informative)
Re:Wireless networks. (Score:1, Offtopic)
Oh my God! These things attract LIGHTNING? Well, I guess that just makes them completely unusable, then. It's too bad... if only we had some sort of device that could protect (lightning) things from lightning (rod)...
Point to Point Laser OC-3 thru OC-192 (Score:1, Interesting)
Re:Wireless networks. (Score:2)
are cool for geeks. I mean WHO DOESN'T have their own intranet in their house???
This is FAR from new technology. I remember looking at one of these in place over 4 years ago. They can by the way traverse 34 miles easily. if both towers are tall enough to be above trees and the curvature of the earth and run at a high power. The problem is that Microwave links are far more reliable. If you get a downpour or thick ground fog your link dies and the biggest problem isnt heavy rain but horizontal rain or freezing rain get some on the UV filter/protector and you now are out of focus until the heaters melt it.
Microwave suffers from more problems.. (98% humidity? you now have heavy attenuation) but you are right. It is cheaper in the long run to buy a pair of dark fibers to your desired location.
Rain, fog, smog, smoke? (Score:2, Interesting)
Re:Rain, fog, smog, smoke? (Score:2, Informative)
Our system worked pretty well - it only covered about 300m, between 2 buildings. Rain wasn't that much of a problem though and we didn't get any fog while it was running. Snow caused some issues, but not enough to really give cause for concern.
What did cause problems were birds sitting on the equipment, and bird droppings which fouled up the receiver. The system was eventually put out of action by golf ball-sized hailstones.
Weather (Score:4, Funny)
Re:Weather (Score:2, Informative)
So the only issue is having objects get placed in the way of the beam; not a big deal for companies that have line-of-site access from the roofs of their buildings -- the only things that'll get in the way thirty feet up are going to be new, taller buildings being built.
My company uses a similar setup (focused microwave rather than IR), and we're quite happy with it. We've had a few small one-second hicups, but that's because they are erecting a new building beween the ones we have radio links on (and yes, the new one is short enough to allow the radio to continue functioning).
Re:Weather (Score:1, Informative)
At the other end of the RF spectrum, at microwave frequencies and lower, the lower frequency wavefronts are so large they don't see the droplets at all, or are only minorly distorted by them. So, microwaves work well 80-90 percent of the time in fog, rain, etc.
Anyway, that's why IR is called "night" vision, not "fog" vision.
Re:Weather (Score:1)
That would be the FLIR system - Forward Looking InfraRed.
Re:Weather (Score:1)
That is why they use an infrared laser. The ray will just melt away the ice and evaporate any rain in the way! Infrared light carries heat, remember?
Re:Weather (Score:2)
Re:Weather (Score:3, Funny)
"Allign it with that building over there."
"What? What building, where?"
Not so funny ... (Score:2)
Also there were often other problems, apparently with the antenna and the signal converter sitting behind it (i only know that sometimes people had to go to the roof to fiddle with the equipment to get the link working again). So you probably should only go for an IR-link if you can stand the occasional downtime, or in sunny countries, where the waether doesn affect the line of sight.
--
What about latency? (Score:3, Insightful)
Re:What about latency? (Score:1)
Don't forget you all freely broadcasting through the air information. Many geeks/hackers with too much time on their hands will have fun with this.
Re:What about latency? (Score:3, Informative)
I think that for gamers 802.11b (or even 802.16 or whatever it is called) makes more sense - no aiming, no major configuration issues. Lots of repeaters if you want to spread over > 100 metres. Sure, anyone can tap in easily - isn't that the point?
Using lasers just complicates things and creates a whole lot more ways for the system to fail than radio frequency spectrum.
For gamers and more generally interactive communications a low ping is more important than huge bandwidth.
Probably the latency will be bad for gamers, but then again are you really suggesting that gamers will want some city wide network for gaming? If they are logging on to some sort of centralised server (ie., where you don't know who you are playing with) wouldn't hitting the internet directly make more sense? Fast connection through high speed routers with a wide audience to find a suitable opponent for a fragfest.
If its a LAN party type thing, then as per above - 802.11b or similar.
If you really need point to point communications, you can still use this sort of technology with a satellite dish and point the signal with similar line of sight accuracy. I know of line of sight RF communications in the 2.4 GHz band over kilometeres.
Re:What about latency? (Score:2)
Re:What about latency? (Score:1)
Re:What about latency? (Score:2)
Re:What about latency? (Score:2)
There are downsides though. The company we talked to is really only interested in selling the equipment to telcos, and is only in the network services business to prove the network works. If I was a shareholder I would also worry that they were willing to provide the equipment (at $90,000 per) so that we could be a network services customer for a couple grand a month.
The technology is pretty cool, apparantly the only weather that affects it is dense fog, and as long as "any" light will pass the link will stay up even if the LOS is obscured by objects. The company we talked to puts cameras in the units so if the link os broken their NOC can actually look out and see if somethin is in the way. Apparantly this came in handy when a cruise ship on the Hudson sailed infront of one of their links.
At the moment they are claiming 99.999 uptime but they do put in terrestrial backup for all of their links.
Later this year they are supposed to release a smaller inside mounted unit that is essentially a replacement for point-to-point 802.11. Nice except for the price tag ~$30,000.
infrared? (Score:5, Funny)
Plywood Fade :-) (Score:5, Funny)
Re:Plywood Fade :-) (Score:1)
Reliability? (Score:1)
Re:Reliability? (Score:1)
Old News (Score:1, Redundant)
Nothing new here... move along
Dr. Evil (Score:2, Funny)
Is this better? (Score:2, Insightful)
Re:Is this better? (Score:1)
-Danga
Re:Is this better? (Score:1)
Re:Is this better? (Score:1)
Re:Is this better? (Score:1)
Re:Is this better? (Score:2)
Re:Is this better? (Score:1)
I think one huge advantage is privacy. The laser is very focused, and eavesdropping would be all but impossible. Although the signal does spread, gets scattered and refracted a lot in unfavorable weather conditions (other posts handle this very capably), it's still a very narrow signal. Compare this with broadcasting radio-signals, where everybody with a compatible receiver within range can eavesdrop. Sure there can (and should be) encryption on broadcast signals, but making the signal physically inaccessible is far superior protection IMHO.
Re:Is this better? (Score:2)
Call the janitor (Score:1)
or
internet is down again. I think there is bird crap on the lenses or the transcever...
ok now seriously what about fog or low clouds on tall buildings? wouldnt that also create noise/bouncback?
what about the pigeons? (Score:1)
SAM will keep the pigeons away! (Score:2)
Re:READ THE FSCKING ARTICLE--IT'S NOT ROOFTOP-MOUN (Score:1)
The lasers can be mounted on buildings' walls or roofs or behind windows, but they all must have one essential: a clear line of sight between the transmitting laser and its receiver
so yes, you can go window to window, but you're not restricted to that.
A side benefit... (Score:3, Funny)
...would be hacking the kernel to transmit remote control waves. Imagine the possibilities:
And if that doesn't work, you could always use it as a spare heat lamp (very desirable when running an overclocked system...)
Re:A side benefit... (Score:1)
packet sniffing made easy (Score:1)
two problems to overcome:
1) how are you going to get up a couple of floors to do this, and
2) what if (and I would hope they do) encrypt the data stream?
Re:packet sniffing made easy (Score:1)
2) How d'you normally encrypt chipered data?
Move ya butt
Old News, and unreliable (Score:1)
The good, the bad. (Score:5, Informative)
primarily in the one time purchase of the equipment. And it makes a lot of sense where line of sight is a shorter distance than a fibre cable must travel (tops of buildings in a congested city). These dont interfere with radio freqencies, so you don't have to concern yourself with noise, or creating noise. And its unlikely a backhoe will ever be a problem (as long as it doesn't block the line of sight).
The downside is the line of sight. You ALWAYS have to have line of sight. Rain, fog, clouds, trees, idiots with signs, they all can cause problems. Short distances are less of a concern, but you still have to maintain an almost perfect orientation. A little gust of wind can have you dropping packets.
But its probably a better solution than fibre where running fibre isn't an economically feasable solution. But no matter how good this is, fibre has far greater potential capacity, even though we don't yet have the technology to use all of it. It doesn't make sense to start building the internet backbone out of these things.
-Restil
Your camera is good! (Score:1)
Use more than one laser (Score:1)
Re:Yeah, that's what "redundancy" means (Score:1)
It's been done for over a decade. "Arclight" (Score:5, Informative)
Arcnet was a self-healing token ring network with an underlying broadcast topology. So if two buildings were connected by Arclight and it went down, the network split into two rings, and when it came back up it healed into a single ring. Reconfig took miliseconds so it was no big deal.
You may not have heard of Datapoint. But have probably heard of the Intel. Seems Datapoint had a discrete-component standalone computer/smart terminal which was the basic node in their network - a diskless-workstation, fileserver, compute-server archetecture. They cut a deal with a semiconductor company called Intel to try to port their instruction set to a silicon chip for the next generation. But the resulting chip was too slow, so they went with another discrete component solution.
And Intel had cut the deal so they could sell the chip. So they took the chip to market, perhaps with a few tweaks, as the 8008 - first in the line that continued with the 8080, 8086, 80x86, Pentium,
Re:It's been done for over a decade. "CanoBeam" (Score:1)
Re:A Decade? Over 25 Years (Score:2)
The roof/pole mounted device was quite large - about the volume of a monitor but twice as deep and half as high, with two big lenses (looking something like eyes) on the front. Curved cover which also overhung the lenses to keep rain of that made it look a bit streamlined, in a style consistent with the '60s and reminiscent of automobiles dating even earlier.
I visited their San Antonio site at one point. They had a sign on the door of the wiring closet behind the server room that was apparently originally intended for a welding machine. It said "do not look into Arc". Seemed appropriate, both as a reference to the high-power infrared link (which was really on the roof) and the truly piled-full-of-snarled-cables wiring closet. B-)
Laser Equivolent of Internet Protocol? (Score:2)
I bet that gigabit lasers with a range of 1 km will become reasonably affordable, because there really wouldn't be much to them. Entire neighborhoods could wire themselves together without requiring permits from anyone (and maybe split the cost of a fiber connection to the internet backbone).
Re:Laser Equivolent of Internet Protocol? (Score:1)
Once again ... the pitfalls ... (Score:5, Informative)
Once a year we have a customer come to us to ask about this option. Once a year we trot out our proposal, rerun the numbers and submit it. It always comes down to two things:
1) Speed
2) Reliability
The speed of the lines is fantastic when you have a clear day and relative distance is kept. Any atmoshperic conditions out of the ordinary will kill the line. Now, if you're only interested in using it for a mail gateway or to transfer data for a nightly batch cycle it rocks. For regular WAN access you'll be answering the phone from the folks on the floor.
Reliability is a concern past the speed. Keeping the connections is sometimes more an art than science. The article does have an interesting take on parallel transmissions, but commerically available products are cost prohibitive to make it a viable alternative for most businesses.
The best line from the article is: "Transmitting lasers through the air and modulating them at gigabit rates is a new and potentially powerful development," said Dr. Daniel Leslie, a physicist at Trex Enterprises who is familiar with the new systems.
Now, if you want to see something cool check out Dr. Leslie's company web page: http://www.trexenterprises.com/laserrad.html
If only we could work a Pringles can into this
True story (Score:2, Funny)
this is not new in the professional arena (Score:1, Informative)
www.laserbit.hu
This has been done for years... (Score:1)
I found that 2.4 or 5 ghz wireless repeated are far more reliable.
lots of applications, lots of promise (Score:5, Interesting)
Divergence, not mentioned in the article, is also an issue. Especially with laser diodes, it doesn't matter what kind of miracle anamorphic lens system you have to decrease the divergence of the beam, becuase pretty soon that pencil thin dot is going to become several feet in diameter. THIS is what accounts to loss more than so called 'atmosphere' causes. Photodiodes/transistors operate at a power/cm^2 ratio, and the lower this is out of the rated area the more noise. So when the beam spreads out, the concentration of power thins out and you get noise because although all your signal is getting there, you can only sample a small fraction of its power. Having low divergence also works against you because it makes the system much more difficult to align. I would start with a very large beam, just enough to get a signal, and then progress to the smallest beam possible. Vibrations at the transmitter site will likely limit this, as tiny shifts in movement only a mm will cause the beam to jump several feet miles away.
Many here have mentioned the speed is on the slow side for this technology. Well, folks, this is optics and that means you can do things in parallel. If you need more speed, just shift the wavelength of the diode and multiplex it in. This is the same principle behind DWDM systems, only it's in freespace. You don't even need a fancy FB diode to do it -- most commercial diodes have a 30 nm linewidth, and by controlling the voltage and temperature you can easily shift up or down. In any case, adding another same-wavelength line is just as easy as adding another transmitter/receiver pair at either end. If only you could do that for fiber. Instead, you have to dig up the streets.
I have had the pleasure of working with a system from Coherent that really makes free space communications shine. The system automatically adjusts and aligns itself via electronic gyros and GPS. It tells you if the current location even has any type of line of sight and if it does it zeos in on the beam (e.g. "I'm pointing S-SW, can you see me?"). The hardest thing is you must have a current connection to the other end while performing the alignment, but this was easily accomidated for at my location with a cellular modem.
This stuff is really cool and there are definate applications for anywhere that has good line of sight. For example, cell towers frequently have good line of sight to one another, so this technology would make sense for that application. There are enough towers that the network could be constructed in a serial or star configuration, without the need for many land lines near the tower.
What would be even cooler would be somehow using the high voltage transmission towers and installing a small, low cost module on each one to jump from tower to tower, or even pole to pole. Since it's optical, you don't have to worry about interference or expensive shielding (yes, there are all-optical transceivers out there).
These are just some ideas but the technology itself finally seems to be maturing. There are lots of current applications and it seems that although most carriers have loads of dark fiber underground, so the cable isn't really the problem, but maybe these companies will help drive bandwidth prices down by enabling small yet very fast ISPs to pop up and use the technology without having to haggle over ground cable. The Internet Revolution per se, isn't going to continue until we all have true broadband (10 Mbps or more, preferably 100 Mbps) to the curb for $19.95 a month.
Home made devices (good link + safety warning!) (Score:3, Informative)
You, yourself, can buy a several watt (yes watt) IR diode
Jesus!
I hope anyone using that kind of power makes sure they know what they are doing.
Because the IR beam is invisible your eye will not have a blink reflex to bright IR light. The first you will know about getting an eyefull of a powerful IR laser is when you blind yourself (or someone else)
You have no pain receptors on your retina.
Remember home made lasers can be an absolute bastard to align! A good staring point for information on home made lasers is Sams Laser FAQ [repairfaq.org]
A good background to semicondutor lasers is Britney Spears Guide to Semiconductor Physics [britneyspears.ac] (Yep, its true! check out the link.)
Xerox Parc did this in the 70s... (Score:3, Interesting)
In order to get the laser printer working from their ethernet computer network (both of which they invented) they had to connect from one building to another. The "easiest" way was to use two lasers from the roof of the building. They had to bring it down as in the fog it was kind of distracting to neighbours and aircraft.
Just out of curiosity... (Score:2)
Doesn't that sound like a commercial? (Score:2)
Order now, operators are standing buy.
lots of IR beams, and one tall building (Score:1)
It's a great idea, and I can imagine people setting up IR beams between their various campuses to get fast networks.
The only problem is, what control do you have over the airspace rights over your line-of-sight? How do you prevent someone building an office tower that blocks 10,000 IR beams? After all, you have purchased no rights to that space, you're simply relying on the fact there is currently no obstacle. if you eventaully complain, the owners and former owners might ask for twenty years back rent on the air space!
Amazing the restraint everybody has today. (Score:2, Interesting)
I'm surprised nobody's brought up the do-it-yourself option:
RONJA [mff.cuni.cz]
It's been on slashdot a couple of times.
Sure it only uses LEDs but it could use lasers rather easily. It would only up the price, and possibly increase the bandwidth.
And...? (Score:1)
Re:And...? (Score:1)
Water acts like a lens and would deform the signal if you ask me.
I still thing you have a more secure connection is you use fiber.
Fiber is harder to tab into. If you use a direct beam from one building to another you can tab into it by just using a few prisms.
Another problem I see is that buildings are moving with the wind. So you would loose connection in storms etc.
If you ask me you would be better off with a RFC-1149 [com.com] connection between two buildings
IR networking in London (Score:1, Interesting)
They also use fibre and SDSL links, which are cheaper in most cases - they have only used lasers in the special cases where it's cheaper than fibre.
Think about mirror-window-thingies (Score:1)
These windows have the added bonus that they tend to reflect *any* kind of optical ray everywhere but inside.
In other words, this does not work, we tried and switched the whole lot for a radiowave solution after finding out that a UTP cable from one office building to the next also wasn't too practical. Birds kept s(h)itting on it, resulting in more packet loss than was acceptable. And it sorta made strange patterns in the wind too, I don't think it would pass any sort of city security council.
Ah well...
These things made my life hell (Score:1)
"LASER" (Score:1)
While it's technically not a "laser", I feel its worth mentioning since I couldn't really have developed a healthy paunch without it.
Thats all great (Score:2)
Fiber (Score:1)
A humble suggestion.. (Score:1)
Both should be X times cheaper than tearing up a sizable portion of a pavement..
Massive wireless Intranet (Score:1)
If the complex pays for a single t1 line, every apartment would have incredible internet speeds.
Talk about a good start up idea for every out of work techie out there. Start visiting these complexes, and offering your services to set up all the back end stuff. I'll bet they would jump at the chance. A single smart guy ought to be able to maintain the equipment for several complexes, and I'll bet you could charge monthly fees per unit.
Wouldn't work here (Score:1)
Perhaps if they up the wattage... so that it burns through the rain/snow/birds...
Possible.... but Impossible (Score:1)
Firstly, the link either should support Ethernet or be connected to the PC serving as a router. It's easy to make a, say, 38400 bps link using the laser pointer and infrared receiver from the TV remote control, but in the country where the average salary is $100 per month it will be impossible to find money for the router PC.
The 10-mbit/s link is much more sophisticated, and if you can produce it you can much easier obtain enough money to buy a 802.11. At least, living in a big enough city I cannot see-and-buy all the parts necessary to produce the link having the full schematics. Of course, I can order them and risk obtaining everything except the one critical part.
I dont't discuss the special extra rugged tripod for the roof-mounting of all this illumination, bands of young vandals, necessity to obtain the roof access permit (I don't need it, but in Moscow it's a rule!), old crazy ladies calling KGB and informing about the martians landing on the roof, necessity to place somewhere a router PC that produces the infernal noise and the Communication Supervision authority that begins to want a lot of money every time when the network gives a first cent of profit.
So the typical Russian LAN still uses the UTP, Ethernet and the military phone cables hanging between the buildings. These cables give the excellent ranges!
Don't use infrared! (Score:1)
Then why not use a high-power laser? If the light were visible, I think the effect might even look cool. Imagine all of the buildings on campus connected by glowing beams of light! Of course, the lasers would have to be far enough above the ground to prevent terrorists from disrupting the network with duct tape or umbrellas.
Think Redundancy! (Score:2)
Ibm Commerical (Score:2, Funny)
"The networks down."
"OH MY GOD!"
"WHY!"
"BIRDS, BIRDS EVERYWHERE BLOCKING IR?"
"WHATS IR?"
You are SO ready for IBM infastructure.
We're doing this where I work (Score:2, Informative)
Our transmitters and receivers are mounted inside our buildings in offices which face each other (the buildings are about three miles apart, as the crow flies) The only problem is the users whose offices are near the laser-office--they've lodged (FUD) complaints about possible radiation and cancer and blindness and fatigue-related illnesses.
We told 'em that at least they didn't have to walk downstairs to the commisary to microwave their lunches.
what about pigeons?! (Score:2, Interesting)
Login: Use This (Score:2)
Password: "slashdot"
I tried to log in as "slashdot", with password "slashdot", which someone on Slashdot usually sets up. It told me, first of all, that my address "FakeAddress@hotmail.com" was already taken. (!) But then it started saying that "Slashdot" was already taken, and started tacking random numbers onto the end. So I finally got frustrated and registered "crappywebsite", given how long it took to register an account... *grin*
from the title: (Score:2)
-1 Redundant
Re:NY Times (Score:1)
e.g. http://archive.nytimes.com/2002/02/07/technology/
Re:NY Times (Score:1)
Re:NY Times (Score:1)
Re:NY Times (Score:1)
Re:Super powered lasers are the way to go (Score:1)
Re:Well... (Score:1)
Re:Old news (Score:1, Troll)
Re:Old news (Score:1)
I saw a segment on these things on CNN over a year ago
Your post:
Hmm
Great reading skills.
Your post again:
you are actually the reason that Slashdot hasn't posted this article until now, as it's YOUR job to send in news
My job? That must be where all those paychecks are coming from. Kind of wondered about that. First of all, it's usually pretty safe to say that anything that appears on CNN Headline news has usually been beaten to death on Slashdot for about a year. Secondly, after having 20-30 articles rejected on this account and my last (including several that were posted about 2-3 weeks after the story was rejected) I decided to stop. I wouldn't be suprised if I actually did submit this story a year ago. I love the "shut the fuck up" at the end too. Always makes me laugh.