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Pure Optical Network Switches
richi wrote to us about the all optical switch that was announced from Agilent. The primary reason for the coolness factor is that an optical switch means that an optical signal doesn't need to be converted into electric at the switch, then back to optical.
See The Coming of the Fibersphere, a great essay about something that this switch makes possible.
eheheh, j/k
here's the link.
http://biz.yahoo.com/bw/000306/ca_ agilent_2.html
Worst Sig Ever
I expect the URL should be: Agilent
All Optical! I have been waiting for this. Now what about the dark fiber?
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Lucent did this about, what, a year ago? Read here. Nortel has already done this as well. Here's the Nortel link.
Optical switching is really cool, don't get me wrong! The slowest link in any big telco network is the switching equipment. How are you going to resolve Nortel's new 2.4Terabit pipes with OC-3 or OC-12 switching technology? Guess what, not happening.
Have a read about what Lucent and Nortel are doing...very cool stuff.
Copper won't be cheaper once fiber optics becomes the dominant infrastructure in the developed world.
Also, there is the little problem that copper itself is a fairly valuable metal. Third world peasants have a tendency to dig up any copper wire infrastructure that is not guarded, and sell it on the black market. Fiber optics, being nothing more than glass, has virtually no scrap value.
I don't see optical switches coming to Mozambique anytime soon.
That's because you won't be seeing much of anything coming to Mozambique soon. By the time they can afford more infrasture, fiber optics should have become the standard in the developed world.
Well, on Agilent's website, they say they use planar-lightwave circuits (whatever they are) that intersect at cross points. In the cross points, there's a fluid that allows the optical signal to pass through uninhibited. To reroute the signal, they insert bubbles into the cross point. The bubble refracts the signal, sending it to a different circuit. They say the bubbles can be generated and removed "hundreds of times per second". (See Introducing the Agilent Photonic Switching Platform for more technical details.)
So, my question is: Have they perfected some way of creating bubbles of the exact same size every single time, and if so, how? Bubbles don't seem (to me) to be something you can regulate by size easily. Anyone with more info, I'd love to be further informed.
Eruantalon
Eruantalon
The Annals of Middle-earth
Agreed optical has the greater potential, but do we know how much more we can squeaze out of copper? We are already doing much more than was once thought practical.
Also, I hope that when fiber optics finally make it to our homes, it will be a hybrid fiber/copper system, because even when we no longer use copper for bandwidth, it would be nice to have it there for electrical power.
I don't like the idea of my telephone having to rely on the power company in order to work. Phones now never go down (unless the line is cut) because they can draw their power over the copper phone line. If the phone companies are smart, they will keep this feature, and thus copper should still be around in some form.
Sort of make sense, since curved surfaces reflect, and they're easier to create in a machine than planar surfaces. Image of soap bubbles of different sizes appearing to be different colors, depending on their size (curvature) comes to mind. Bubbles are a natural shape - ever try to blow a square bubble? :) I wonder what substance they propose using?
:)
;P
If they propose to bounce the pulses off of bubble surfaces, they'll distort them. BUT, if they bounce them AGAIN from an identical bubble, they'll (should) be restored. Interesting.
Then again, it might be a hidden message. What do you need to blow bubbles? Air, preferably hot air. Well, some sort of vapor anyway. Vaporware.
And if the quality of the waveform is as good as the quality of inkjet printouts, we'll have to design a polymorphic iris for the optical receivers, so they could squint into the fiber to make out the signal!
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My reading of the article is that it is a less responsive level of switching. It is the equivalent of a phone exchange or patch panel that allows you to change the connectivity between a set of fibres. Obviously there is some other method of sending information on which pairs to connect together. Also I would guess the mechanism that generates the bubble is electricity based (though I may be wrong).
I don't see that this particular technology could be used to switch at the packet level simply because bubbles cannot be created or removed fast enough (we're talking moving physical matter so information would be lost in transition). Or maybe the system can only switch a thousand packets a second. Big gaps but boy do they move fast.
Optical computers require the switching to be instantaneous and driven by light itself (photoreactive or some such). Using this technology in optical computers would be like using relay switches in electrical computers. However relays at least used to be used in MAUs to connect computers together in a network.
This technology is useful for the infrastructure of optical computing systems but we need the optical equivalent of the valve or transistor (light amplified or switched using only light) to build the actual optical processor.
Gamma Testing - Where testing is extended to the full user community (AKA Shipping the Program)
This is a rather important development for optical networks. Other than the initial energy source and the receptor at the end of the line, this technology may be the last piece required for a fully optical system.
The previous important development in optical transmission networks was the optical amplifier. By doped sections of fiber with a high voltage placed across each section, they were able to create an amplifier. The light waves coming into the doped section of fiber would be amplified.
To briefly describe it, imagine blinking a small flashlight into a window. On the other side of the glass it looks like a car's headlight rather than a small flashlight.
Ok, this amplifier is cool but why is it important. The amplifier allowed companies to move away from light to electric to light. In fiber optic system, the signal decays as it travels through the fiber. Once it reaches a certain level, it will become unusable. Thus, you have to boost the signal periodically. Traditionally, communication companies had to take the decayed signal, convert it to electric, then you drive another laser with the weak electric signal. This then completes the light to electric to light again, and you now have a usable signal again. (Until you have to boost the signal again) Anyway, this conversion process created a whole new set of problems. By converting it to electric, you introduced noise. After a "amplifying" the signal a few times, your signal was no longer clean buy now included some noise.
This optical amplifier was important and lead to the FLAG system. If you read Wired a few years ago, they did a really good job of discussing FLAG. FLAG is the "Fiber Optic Link 'round the Globe" and is a _large_ undersea fiber optic cable reaching from UK, to Egypt, to Malaysia, to Japan. This project and other like it, became feasible because of optical amplifiers.
Optical switches are important for the same reason. It will reduce noise and increase reliability of the system.
I would not look to see these switches replace the current technology (as mentioned in a previous post). However, I would expect to see these switches start to become incorporated into new systems such as subsea communication, pipeline right-of-way bandwidth, or other cross country communication networks. There already is a big market for piping ESPN to parts of the country. Imagine that you could route the information more like a phone system than a gas pipeline. This could create a whole new market.
Hundreds of times a second? Please, we're moving to optical because of the bandwidth. Communications at the speed of light (in glass or plastic). We're talking multi-gigabits per second. And we want to switch packets at that speed with switches that can switch hundreds of times a second? Who can ponder the packet sizes required; megabytes to be sure.
Sorry, but switches that require the physical motion of sizeable amounts matter don't cut it for optical communications. If they were talking about nanotechnology, that might be another thing. But as it stands, this must be a warm-up for an April Fool's joke.
Uwe Wolfgang Radu
Well, as a Network Engineering Consultant in a Heavy Nortel Shop, I have had a chance to see the OPTera and Verselar 25000 in action. These devices are Electro/Optical not pure optical and I believe the break through with the Aligent device is that it is purely optical.
The Economics of Website Security
Yesterday the link of a large european ISP went down, because they tried to replace the custom bubble-liquid cartridges of their HP optical switches with an el-cheapo no-name product. Other networks stalled when admins tried to refill their switches using a syringe... :-)
BTW, dont they have to determine where to swicht what? And they sure dont do that optically, so its still the copper and circuits slowing them down, not? Any answers?
That's not what this is designed for. You'd actually use it for things like this:
If a backbone node goes down, it's not going to go back up a microsecond later. You want to switch _all_ traffic to an alternate route, and then switch it back a few minutes or hours later when the node goes up again.
Think of this switch as acting something like a crossbar bus, connecting pipes point-to-point. Need more bandwidth between point a and point b? Allocate an additional pipe connecting them. Not using all bandwidth? Remove a pipe and allocate it to another pair of servers. Load patterns vary over minutes or hours, not microseconds, so this works fine.
Now, a purely-optical switch that _could_ work on the microsecond or nanosecond level would be very nice; however, a slower switch is still very useful.
An optical switch is one thing, but it doesn't do much that a technician swapping cables can't do (only slower). An optical router , now, that would be the biggest enabling technology for an all-optical network. It's also the most difficult.
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Time is Nature's way of keeping everything from happening at once... the bitch.
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Time is Nature's way of keeping everything from happening at once... the bitch.
Their claim is "pure optical is faster than optical-electronic-optical", but their system is "optical-bubble optical"--very slow.
I'm not sure just how fast the inkjet guys can make bubbles, but I estimate ~10,000/sec max based on printing rates. Compare than to MEMS mirrors and diffraction gratings which have been around for 10+ years and operate 10-100 times faster!
Bubbles sure as hell aren't replacing III-V semiconductor electro-optical devices, unless you can make about 10,000,000,000 bubbles/sec...
Many years ago there was an article in Scientific American about fiber optic telephone networks. It had a description of a prototype telephone designed by Northern Telecom that used fiber instead of copper. The telephone converted light to electrical energy to power its circuits. I don't remember what they used for a ringer.
Mea navis aericumbens anguillis abundat
I want a 100Mb/sec fiber pipe to my condo, and I want it now! (grin)
Dig up any copper ..., and sell it in the black market Well, I happend to live in Mexico, and the real problem were people diggin up fiber optics equipment because it reaches a higher price on the black market than copper. I think people tend to steal things which are expensive, copper is just not valuable enough. That was/is the reason why most communications systems in development countries use micro-waves
42 cows on a 42km road on their way to 42.org
This is a good step forward, but it's not the type of switch most people assume when they see the word 'switch'. It looks like Agilent has the world's first pure optical cross connect, which is a significant development.
Single fibres are never installed, there are always multiples, so that if one gets damaged/breaks/hit by backhoe, there is another that (hopefully) didn't get damanged, and the equipment switches to the backup. That's the application I see for this Agilent development.
Transmitters for 2.4 Gbit/S optics are EXPENSIVE, can generate a lot of HEAT, and are fairly LARGE. So if you have multiple redundant connections, you currently need mulitple redundant transmitters! Not a great investment... BUT if you can take 1 transmitter and use a 'pure-optical switch' (better known, probably, as a cross-connect) to connect it to one of N possible fibres, well... it saves money and could improve reliability.
Not only that, but it's independent of the actual technology on the fibre. So it can switch OC-3's (155 MHz-ish), OC-12's (622 MHz-ish), OC-48's (2.4 GHz-ish), and wave-division multiplexed (multi-wavelength lasers on a single fibre) without caring about it... 'cause it's just a mirror!
This is a Good Thing (tm). HP might not be the first to do it (I had a college professor that was using microelectronic machines [MEMS] to do something similar), but it seems they might be the first to mass-product it.