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Fiber Optic World Records Broken
Thousands of miles of existing fiber still lie dark, but as
schnucki writes, "Bell Laboratories believe they have broken two world records in the use of optical fibres to transmit information." They sent 160 gigabits/sec on one wavelength, and then in a separate experiment sent 1,022 separate wavelengths down one fiber. You do the math.
Check it out.
I am getting 21600 on my 56K modem at my new apartment? Did I win anything?
Funny and I thought Perl == Paid employment recently located
The first record promises to increase speed.
Woohoo! No more poxy 299,792,458m/s! According to relativity, this means that the data can go backwards in time. Soon we'll all be complaining about anti-latency.
Normally I wouldn't nitpick the BBC[1], but seeing as they split an infinitive in the last paragraph, I felt I had no choice.
[1]This is a lie.
I'd like to have that running into my home. Perhaps we could use SimCity to demonstrate the traffic surge that will generate? The subways could be the fibers, put some commerce, here, there. Cram the schools in the lower corner, Why does SimCity insist that there have to be power generators inside the internet?
Someone set us up the bomb, so shine we are!
To give a bit of background, fiberoptics is just a small glass (or other clear substance) thread, which provides a container for light to bounce through. The light always goes at the same speed (I know that isn't quite true, but close enough for this discussion).
The data rate achieved is based on the frequencies that are transmitted. So, in order to get the higher data rates, higher frequencies are needed. (Generally.)
"Why should I be content to simply live in this world, when I, as a human being, can CREATE it?" - Oertel
I'm just curious what the error rate is. Can you send that much data without loosing a few bits. I'm impressed with the numbers regardless, but if you have a 50% error rate is that good? Also if you loose one bit per byte, can you clam anything? Did they only count the good bits sent?
;). If you send 160 Gb/s (20 GB/s), can you convert that to electrical data without making a bottleneck. I'm not an expert in this area, but I'm curious to know.
Also, what is the speed to transfer the light signals to electrical. I don't have (or have I ever heard of) an optical computer, would be nice though
Steven Rostedt
Steven Rostedt
-- Nevermind
What they are doing here is called WDM (wave division multiplexing). There has been a standard for a while on WDM. But the thing is this only allows you to cram more information down one pipe it doesn't shrink the equipment on either end. They need to stick in and OC-48 for each wave length, so you would need about 1 foot ball field of space to stick all of the equiptment for this one piece of fiber. To sum it up don't expect to see any dramatic speedups anytime soon
They claim all 1022 wavelengths were transmitted at the same time with an ultra fast laser. I thought lasers emitted coherent light at one wavelength. I have seen adjustable lasers, but it was one wavelength at a time and depended on tube geometry and the die used. How do they tune their laser to transmit multiple frequencies at the same time? It sounds unbeleivable to me.
And boy, will that ever give us more bandwidth to support the increasing numbers of cellular phones!
(Um, oops... How do you get the fibre cables out to the phones?)
If you're not part of the solution, you're part of the precipitate.
Vacuous futurist idea: Imagine a very small machine that burrows from a central office/switch to your basement with very little operator attention. As it burrows it's dragging along a strand or two of lovely fiber.
Listen to me whine! I'm lucky enough to have a cable modem and I'm STILL not content!
License: By reading this you are agreeing that you agree with me.
Light can indeed cancel itself. Think of defraction patterns caused by coherent light mixed 180 degrees out of phase with itself. My physics is a little rusty, but I'm interested in fundamental harmonics created by other modulated wavelengths.
I think the most impacting news is that optic "router". That is going to have the biggest effect. We dont' need 160gb/s if it has to be converted into an electronic signal everytime it switches fiber lines.
This isn't really revolutionary new technology.. we've known about stuff like this for awhile. There's a nearly infinite number of ways to encode frequencies, and stack things onto each other.
I find myself wanting of the ability to insert IMG tags here. :( In short, picture a sine wave. Now along the slope of one, picture another sine wave attached to it. And so on. I suspect they're doing something like that. Actually, TVs do something like this - it's how the sync pulses and whatnot work. Very facinating technology. Also very old by today's standard, but still very useful.
--
Qwest has their fiber-optic lines setup so you don't need to dig them up to replace them. They just yank them out of the conduit. They have 2 conduits set up, one is full right now, the other is empty (if I recall), so they can string the fiber in it, with no digging up the lines.
Older companies like AT&T have to do more work to redo their fiber lines.
BTW, a post further down the line here there is a post which implies that Lucent makes fiber-optic lines for sale. I know they do optical research, but Corning makes the majority of the optical lines sold. Corning's symbol is GLW for interested investors.
No, not at todays processing speeds. You could though push electrons through copper at roughly the speed of light. Think of it like this. You have marbles(electrons), and a pipe(copper or any other conductive medium). You can push the marbles through the copper to near the speed of light, but due to laws of relativity the electrons will never be able to be transmitted the speed of light.
(Feel free to modify words in that sentence so as to provide bad jokes. There are ample options available...)
If you're not part of the solution, you're part of the precipitate.
160,000,000,000 * 1022 = 163,520,000,000,000 bits
163,520,000,000,000 / 8 = 20,440,000,000,000 bytes
20,440,000,000,000 / 1024 = 19,960,937,500 kbytes
19,960,937,500 / 1024 = 19,493,103.02734375 Mbytes
19,493,103.02734375 / 1024 = 19036.233425140381 Gbytes
19036.23342514038 / 1024 = 18.590071704239 Tbytes
That is some bandwidth on ONE FIBER....
-- iCEBaLM
can it do 160gb/s over all 1022 channels?
What's wrong with cable modem? It modulates and demodulates, right?
--
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Time is Nature's way of keeping everything from happening at once... the bitch.
yup...99% of all cable is carrying analog waves, which makes it a cable modem (MODulator/DEModulator)
My journal has hot
Varying the intensity of a light source creates "sidebands", the same as it does for RF. These "sidebands" are wavelengths slightly longer and shorter than the "carrier". What you see as an amplitude variation is really the interference of the carrier and the sidebands, as they slip in (high amplitude) and out (low amplitude) of phase over time. If you have a carrier frequency of F and a modulation frequency of M, you'll create sidebands at F+M and F-M. If you have really good filters you can suppress one of the sidebands and still carry all the information, and if you have really good frequency references as well you can ditch the carrier and only bother sending one sideband (you can use the frequency reference at the receiving end to supply the "carrier" for demodulation); this is how SSB radios work.
What does this mean for optical fiber? It limits how close together your "colors" can be based on how fast each one is modulated. The sidebands get farther and farther from the carrier as the modulation gets faster, and if the sidebands start clashing you get crosstalk and data errors.
--
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Time is Nature's way of keeping everything from happening at once... the bitch.
The speed of light through any medium is less than the speed of light in a vacuum. Sometimes light can be made to travel through a medium faster than it's natural rate. This results in a nifty "light shockwave" which I believe is called cherenkov radiation.
:-)
Yep. You can see some cool pics of this effect at http://www.nuc.umr.edu/Reactor/Reactor.ht ml, along with a pretty good explanation of how. It's pretty neat the way it actually happens..
Furthermore, the light in a fiber actually zig-zags down the fiber channel and does not travel straight down it. This also reduces the signal's speed from c.
Actually it increases the distance of travel which gives an appearent speed difference from c, which is just as good as slowing it down.
---
- Give a man a fire and he's warm for a day, but set him on fire and he's warm for the rest of his life.
it's often been said (though I'm not sure how true it is now) that current data transfer methods may seem fast, but they still don't beat the "data transfer rates" of simply filling a stationwagon full of data tapes, and driving it yourself to the destination.
:o)
:o)
True, but the thing that this approch doesn't take into account is latency. (which, depending on the length of the drive, and how long it takes to load/unload the stationwagon, can range from ~5 minutes, to several days..)
If I'm playing a game of quake, I'll get my ass whopped if I rely on the stationwagon method
I think that (although the bandwith is considerably smaller) this is a step in the right direction.
*sigh* People keep getting rate of propogation confused with rate of transfer. This is latency vs. bandwidth folks.
For instance, consider the ancient communication method consisting of two people atop hills signalling with lanterns and shades. The latency is really low because the light propogates at near 3e8 m/s in air. The bandwidth sucks. Now consider a freight-train loaded to the gills with DVD-ROMs. The bandwidth is enormous, but the latency sucks.
The speed of light governs how quickly a packet of data gets from point A to point B. Bandwidth measures the total number of packets of data that you can send from point A to point B at a given time. The two are different, unless you somehow treat each photon as its own packet of data, and we're not there yet.
--Joe--
Program Intellivision!
We'll run fiber to the homes shortly, if something isn't developed soon that's even better. (Take a look at the recent Scientific American articles on the current candidates.)
Individual fibers to the home are a lot of bux. But a multiwavelengh fiber to the neighborhood and a passive wavelength divider (think prisim) and a bunch of short fibers to the house look like a good cost-tradeoff.
But having the government pay for it means you get to pay for whichever solution they chose at least three times - once for the install, twice more for the administrators. And the government will chose the wrong one. And the government won't even chose the best price/performance combo for the data rate they do chose.
Sure the government built the Interstates (kinda). And then they installed a 55 MPH speed limit - city, prarie, or deserted desert. Let them wire your home (or your kid's school) and they'll do it badly, expensively, and use it as a wedge to control the content.
The fact that I can plug in a *crank* telephone (not pushbutton, not rotary,... a crank phone) from 189x and *still* use it to make and receive calls on POTS lines should say something about the state of telephone tech in supposed advanced nations like the US.
Actually, it says more about good standards lasting a long time. Just like the Roman's choice of wheel spacing affecting cars, trains, and spacecraft components (that are shipped on trains) to this day.
The POTS standard is about getting audio from the switch in the city to the houses in the city and to the farms around it. The last mile of the audio part of that job hasn't changed materially since Bell and Strowager. A cheap low-tech solution does it, so why pay a bunch of bux to replace it with something that doesn't interact? Especially when doing so creates an administrative nightmare for no advantage.
Data is now hitting the wall on the capacity of the infrastructure designed for voice, so you need to replace part or all of it to go beyond.
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
I think that they called them feelies in Brave New World...
If you're not part of the solution, you're part of the precipitate.
But funny! so please don't mark this down :-)
Winston Churchill is reputed to have answered, when accused of ending a sentence with a preposition, "That is something up with which I shall not put".
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Infuriate left and right
But since this is all put together from sinewaves, which are nice and continuous, how the heck do you get a corner? In practice you can't, because it requires frequency components out to infinity (and infinite bandwidth!). But even an approximation of that "corner" requires other frequency components which add during the high-amplitude section, and then they all come together at the "corner" and suddenly they all subtract from the "carrier" for the low-amplitude section. All of these different frequency components mean lots and LOTS of sidebands. You can hear this in Morse code communications; if a keying network isn't set correctly and it cuts the signal off abruptly, you can hear the sidebands (key clicks) far away from the sender's carrier frequency. An over-modulated AM signal that "flat-tops" (clips)or cuts off completely causes broadband "splatter" which can be heard well off the channel too.
The way to limit bandwidth is to vary things smoothly, with no edges or corners. It may not be intuitive, but this is an area where your intuition doesn't get much experience.
--
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Time is Nature's way of keeping everything from happening at once... the bitch.
You can derive the result of amplitude modulation from the trignometric identity:
sin(a) * sin(b) = sin(a+b) + sin(a-b)
By treating the carrier as a sine wave and the modulation as a sum of sine waves, and using the normal properties of real-number multiplication and addition you can work out the spectrum that results from amplitude modulating a carrier with any periodic waveform. It gets slightly more complicated for aperiodic waveforms, but the basic result is the same: A pair of sidebands, on either side of the carrier, that reproduce the spectrum of the modulating signal.
To send more bits on an AM carrier you essentially have to either modulate the signal faster (spreading out the spectrum of the modulating signal and thus that of the modulated signal) or modulate it more finely (using more bits to control the amplitude). The number of bits you can cram into the second is limited by the signal-to-noise ration of the channel (i.e. when you get near the noise your least significant bits get corrupted).
The Nyquist sampling criterion gives you a quantitative limit on this: If you have a band-limited signal, you can encode it with a number of bits-per-second equal to 2 times the bandwidth times the base-2 log of the signal-to-noise ratio, and reproduce it to within the the noise threshold. So that's the absolute maximum number of bits the signal can carry.
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
Read bell labs blurb on their web site here they do get a /bit/ more technical...not much though i'm afraid...