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Scientists Double Optical Fiber Transmission Capacity

ms writes: "Yesterday golem.de reported that the Optical Communication and High-Frequency Engineering Group at the University of Paderborn (Germany) claims to have made a technology practical which doubles the transmission capacity of optical fibers to 80 GBit/s. In their so-called "polarization division multiplex data transmission system" they don't only send one but two mutually orthogonal light waves through the fiber. They say the only big problem was the dispersal of the light waves which limits the data rate. Additional they had to fight against the phenomena that the polarization direction of the light waves changes while it goes through the fiber. Now, after two years of research, they invented an "automatic optical compensator of polarization mode dispersion" which fights both the limitations. With this gadget they were able to send data at a rate of twice 40 GBit/s (that's 85,899,345,920 Bps) over a test-line of 212 km. And "only the available equipment limited distance and data rate". As we all know, optical fibers build the (cronically overloaded) backbone of our beloved Net. (BTW: That's Net., not .Net!)" Here's the babelfish translation, too.

8 of 229 comments (clear)

  1. I love bablefish! by nizo · · Score: 5, Funny
    From the babelfish translation:


    Additionally it possesses a controlling mean, which is to after-pursue even largest polarization modifications, as they occur on very long transmission circuits contrary to competitive systems also, noly-break.

    Once I figure out what a noly-break is, I should be able to build my very own high speed home network!

  2. Increasing capacity; increasing vulnerablility by case_igl · · Score: 5, Insightful

    It seems every year we find a way to double the amount of data that we can send down fiber. As a result of this, companies are actually deploying less new fiber in the field and taking older lines out of commission.

    One of the things that worries me about this is the increased vulnerability. In the past, huge fiber networks were used that can be one tenth the size today. All too often a clueless construction worker rips up a section of fiber and causes some havok.

    Won't this kind of thing happen more frequently if less fiber is deployed that can handle more traffic? And does this bring us any closer to fiber to the curb - it doesn't seem like it.

    1. Re:Increasing capacity; increasing vulnerablility by sllort · · Score: 5, Interesting

      All too often a clueless construction worker rips up a section of fiber and causes some havok.

      The industry euphimism for this phenomenon is a "backhoe failure". Metro fiberoptics are all deployed in a "ring" configuration - if a ring is cut, the traffic is sent the other direction on the ring withing 50 milliseconds. The operative protocol here is called SONET. SONET rings have been around for a long time, and they pretty much solve the issue of backhoe failures. Some vendors are pushing proprietary mesh-based architectures which offer even more redundancy.

      The issue you bring up, however, does exist on one-way long-haul fiberoptic lines. Major carriers spend millions on 24 hour overflights by patrol helicopters to monitor these fibers for cuts - and some of the largest players in the telco field are oil suppliers because they already patrol their oil pipelines for just this kind of event; burying fiber next to the pipeline is cheap by comparison.

      The massive transmission capabilities introduced by advances in fiberoptics DO give us more ability to heal networks, because they give us additional load-bearing capability during failure. The missing piece is actually building equipment which will heal the network effectively, in time. If you're truly interested in ongoing research in this area, open up google and ask it about "GMPLS".

      Enjoy.

  3. Re:Dark fiber by sllort · · Score: 5, Insightful

    This is going to help the industry alot. Right now there is pleanty of unused fiber, but the problem is the devices that use the fiber take too much room. if we build them smaller and faster we can increase capacity easily.

    The other thing that would help the industry would be to stop going bankrupt. Most to all of the CLECs (PS/Inet anyone?) are bankrupt and insolvent, and the major carriers - WorldCom, Verizon, Global Crossing - have horrible credit ratings and a total freeze on capital equipment purchasing. Right now no one is buying next generation optical equipment. Look at Nortel stock... if you bought $1000 of Nortel stock last year, you'd have $43 today. I won't even mention Lucent. Those are the big boys - the small ones (cough Iron Bridge cough) are all dead or dying.

    Optical equipment vendors have no customers. Optical equipment manufacturers are slashing R&D and personnel, and relying on existing revenue streams for survival.
    Optical network carriers are nearly bankrupt.

    ...and NO ONE is paying for premium bandwidth.

    So pretty much, this isn't gonna help anybody. The next advance in optical networking isn't going to be the next next-generation fiberoptic breakthrough. It's going to be a solvent carrier, or a paying customer for broadband.

  4. mutually orthogonal by MarkusQ · · Score: 5, Informative
    Just trying to grok "mutually orthogonal". Is that redundant, or just over my head? Not trying to nitpick, but to understand something my networking prof never explained.

    "mutually orthogonal" means (for a set of two or more elements) that each pair of elements is orthogonal--AFAIK, it's a synonym for "pairwise orthogonal". "orthogonal," of course, has lots of synonyms, including "linear independence," "at right angles," "having zero dot-product," "statistically uncorrelated," etc.

    So, the three spacial dimensions, the set {phase of the moon, day of the week, time of day}, etc. are all "mutually orthogonal." When talking about a set of only two elements, the "mutually" is superfluous, but not redundant.

    -- MarkusQ

  5. Re:Slashdot posters have a short memory by sllort · · Score: 5, Informative

    Hmm, and same Timothy posted this article [slashdot.org] on June 25th about a lot of fiberoptic cables that have been put into the ground but haven't been put to work.
    You gotta love the consistency of Slashdot posts :)


    Dark fiber is fiber with no optical equipment connected to it. Fiber is not the expensive part of optical networking. Air-conditioned environment-controlled closet space filled with millions of dollars of self-healing optical equipment is the expensive part. A lot of metro optical carriers use the benchmark of $100,000 per month per 7 foot rack in operating costs. The denser the equipment, the cheaper the equipment, the more of that dark fiber the carriers can light to form the backbone of the Internet.

    So, in short, Slashdot was right and you were totally wrong. Or Insightful. Your choice.

  6. It's the switches, stupid. by NerveGas · · Score: 5, Insightful

    We already have much more fiber capacity than we can use. The real bottleneck of the Internet right now is... the switching. OC-768 units (38.8 gigabits/sec) won't even reach volume production until 2003 or later, and they wouldn't even handle half of one of these fibers, let alone multiple fibers coming from various locations. It's like running a 2" diameter fuel line to the engine of your Hyundai.

    All-optical switches have been developed, but are not going to be widely deployed for some time. I have a feeling that even all-optical switches will be many years before they reach the speeds needed for 80 gb/s fibers.

    The true improvement of the Internet will occur when switching capacity increases by at least an order of magnitude in a very short amount of time. Right now, good, guaranteed bandwidth is barely any less than it was back in 1997. Sure, as switching capacity slowly progresses to fill the needs of the backbone providers, the Internet keeps running - but you still end up paying out the nose for guaranteed bandwidth. Once the switches catch up with the fibers, however, that *might* change. Maybe.

    steve

    --
    Oh, you're not stuck, you're just unable to let go of the onion rings.
  7. Re:Dark fiber by mangu · · Score: 5, Insightful
    The other thing that would help the industry would be to stop going bankrupt.


    That's a normal thing in industries. It happened in the 1890's when railroad equipment manufacturers went bankrupt. It happened in the 1930's when car manufacturers went bankrupt.

    When an industry is growing, a lot of new companies are spawned. Then, there comes a period of readjustment, when the market gets saturated and there is a mass extinction among companies.