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Topic: Wavelength division multiplexing


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In the News (Mon 17 Dec 18)

  
 Wavelength-division multiplexing - Wikipedia, the free encyclopedia
In fibre optic telecommunications, wavelength-division multiplexing (WDM) is a technology which multiplexes multiple optical carrier signals on a single optical fibre by using different wavelengths (colours) of laser light to carry different signals.
WDM wavelengths are positioned in a grid having exactly 100 GHz (about 0.8nm) spacing in optical frequency, with a reference frequency fixed at 193.10 THz (1552.52nm).
An interesting and relatively recent development relating Coarse WDM is the creation of Small Form Factor Pluggable (SFP) transceivers utilizing standardized CWDM wavelengths.
en.wikipedia.org /wiki/Wavelength_division_multiplexing   (1248 words)

  
 Wavelength Division Multiplexing
The cross-connect is composed of wavelength demultiplexers for the input stage, wavelength multiplexers for the output stage, and fibers interconnecting the two stages.
A disadvantage of a single-hop WDM network is that the network and all its components must accommodate N wavelengths, which may be difficult (or impossible) to achieve in a large network.
An alternative to requiring N wavelengths to accommodate N nodes is to have a multihop network, in which two nodes can communicate with each other by sending through a third node, with many such intermediate hops possible.
www2.rad.com /networks/1999/wdm/wdm.htm   (4190 words)

  
 WDM (Wavelength Division Multiplexing) (Linktionary term)
WDM is an FDM (frequency division multiplexing) technique for fiber-optic cable in which multiple optical signal channels are carried across a single strand of fiber at different wavelengths of light.
The frequency increases as the wavelength is shortened.
Best of all, EDFAs can simultaneously boost the signals of multiple wavelengths in the same cable.
www.linktionary.com /w/wdm.html   (791 words)

  
 Dense Wavelength-division Multiplexing
Recently, multiplexers have gained versatility, moving beyond the “wideband” wavelengths and into densely packed wavelengths that can be integrated into a multiple high frequency, 192 to 200 THz, transmission system.
This increase means that the incoming optical signals are assigned to specific wavelengths within a designated frequency band, then multiplexed onto one fiber.
he recent explosion of DWDM technology forced the fiber optic manufacturers to develop DWDM multiplexers and demultiplexers that can handle closely spaced optical wavelengths.
www.fiber-optics.info /articles/dwdm.htm   (1427 words)

  
 Wavelength-Division-Multiplexing Optical Fiber Systems
With wavelength division multiplexing several optical information signals can be transferred in a single optical fiber.
Each of different wavelength laser is operating at the slower Gbps speed but the aggregate system is transmitting at n times the individual laser speed which n is the number of channels in WDM structure.
Wavelength tuning is accomplihed by variying the air gap between the mirrors.
bornova.ege.edu.tr /~uzun/projects/WDM   (3651 words)

  
 Cable University Fiber Tech: Dense Wavelenght Division Multiplexing
WDM only made sense if the multiplexed wavelengths were in the region of the fiber amplifiers operating range of 1520 to 1560 nm.
The technical requirement is only that the lasers be of very specific wavelengths and the wavelengths are very stable, and the DWDM demultiplexers capable of distinguishing each wavelength without crosstalk.
They can amplify numerous wavelengths of light simultaneously, as long as all are in the wavelength range of the FO amplifier.
www.thefoa.org /tech/dwdm.htm   (1110 words)

  
 Coarse Wavelength-division Multiplexing
For more information DWDM or WDM see Dense Wavelength-division Multiplexing or Wavelength-division Multiplexing.
The wide spacing accommodates the uncooled laser wavelength drifts that occurs as the ambient temperature varies.
With a capacity greater than WDM and smaller than DWDM, CWDM allows a modest number of channels, typically eight or less, to be stacked in the 1550 nm region of the fiber called the C-Band.
www.fiber-optics.info /articles/cwdm.htm   (263 words)

  
 Wavelength Division Multiplexing
It is possible to send messages anywhere in the network, include needed codes and instructions for correcting, decrypting, and reading them, and allow each terminal to tune into its own messages on its own wavelength.
Because WDM allows the large bandwidth of the optical fiber to be more fully utilized, optical fiber becomes more than a simple 1:1 replacement for copper wires (one channel per fiber).
The channels are then optically multiplexed such that multiple channels travel down the fiber simultaneously and with negligible interference.
www.lanl.gov /lanp/WDM/wdm.html   (278 words)

  
 Wavelength Division Multiplexing
Wavelength Division Multiplexing (WDM) is used to increase the transmission and reception capability of fiber optic cable systems.
WDM is a technology that transmits different types of data at distinct optical wavelengths – or color of light– over a single fiber channel.
  The WDM multiplexes each together to form a new light signal operating at a different wavelength (l5).
polaris.umuc.edu /~lray/wdm.htm   (500 words)

  
 Wavelength-Division Multiplexing (WDM)
Wavelength-division multiplexing (WDM)_wavelength-division multiplexing (WDM) is an approach that can exploit the huge opto-electronic bandwidth mismatch by requiring that each end-user's equipment operate only at electronic rate, but multiple WDM channels from different end-users may be multiplexed on the same fiber.
In this regard, note that, normally, a lightpath operates on the same wavelength across all fiber links that it traverses, in which case the lightpath is said to satisfy the ^wavelength-continuity constraint.
Lightpaths that cannot be set up due to constraints on routes and wavelengths are said to be blocked, so the corresponding network optimization problem is to minimize this blocking probability.
networks.cs.ucdavis.edu /~mukherje/book/ch01/node4.html   (757 words)

  
 DWDM (Dense Wavelength Division Multiplexing) : Teledatacom Glossary
Dense wavelength division multiplexing (DWDM) is a technology that puts data from different sources together on an optical fiber, with each signal carried at the same time on its own separate light wavelength.
DWDM is also sometimes called wave division multiplexing (WDM).
Using DWDM, up to 80 (and theoretically more) separate wavelengths or channels of data can be multiplexed into a lightstream transmitted on a single optical fiber.
www.artesyncp.com /resources/glossary/dwdm.html   (217 words)

  
 Optical Networking Home Page
The department performs research and development on optoelectronic components, architectures, protocols and complete systems for optical networks that use wavelength division multiplexing (WDM).
The channels are spaced typically 1 nm apart in wavelength (120 GHz apart in frequency) in the 1.5 micron passband of the fiber.
Typical time-division multiplexed systems are limited in their exploitation of this bandwidth for communication by electronic speeds, which currently allow transmission at bit trates of up to a few Gb/s total.
www.research.ibm.com /wdm   (177 words)

  
 WDM (Wavelength Division Multiplexing) : Teledatacom Glossary
Then, lasers of various wavelengths can be transmitted along a single fiber, and each laser can be modulated by its own set of radio-frequency signals.
In a simple fiber optic system, the receiver is not sensitive to the wavelength of the laser.
A visible-red laser might have a wavelength of 735 nanometers (nm), where 1 nm = 10-9 meter.
www.artesyncp.com /resources/glossary/wdm.html   (237 words)

  
 IP over A--Thousand--Wavelength Division Multiplexing: (ResearchIndex)
Abstract: WDM (Wavelength Division Multiplexing) networks are emerging as a practical and future--proof solution to provide the infrastructure of the next generation Internet.
The number of wavelengths is probably a key factor, and then, the question is; is it possible to realize IP over a--thousand--wavelength division multiplexing?
It is still not clear, however, what structure of IP over WDM networks is best suited to satisfy the growing bandwidth requirements in the future Internet.
citeseer.ist.psu.edu /684754.html   (253 words)

  
 All Optical Networking Consortium Executive Summary
We are investigating two promising technologies for utilizing the bandwidth of a fiber: wavelength-division multiplexing (WDM) and time-division multiplexing (TDM), the latter utilizing soliton pulses.
Our architecture addresses all-optical transport over wide, metropolitan, and local areas utilizing wavelength partitioning, wavelength routing, and active multi-wavelength cross-connect switches to achieve a network that is scalable in the number of users, data rates, and geographic span.
We have developed a 20 channel local and metropolitan area WDM test-bed that is deployed in the Boston area that is based on the architectural principles using advanced components.
www.ll.mit.edu /aon/executiveSummary.html   (517 words)

  
 Links to sites regarding Wavelength Division Multiplexing
Deep material on designing FBGs which compensate for the differing propagation speeds of differing wavelengths in the hundred or so kilometres of fibre which precedes it.
Their plans for un-repeatered links based on eight 10 Gbps channels of WDM per fibre (with optical amplifers, but no opto-electrical-opto regeneration) across the Pacific (New Zealand to Chile) seem to be beyond the current technology, due at least to polarisation mode dispersion, and quite likely other limitations, especially signal-to-noise ratio after several dozen EDFAs.
It depends on WDM, and is yet to recieve the support of the major telcos.
www.firstpr.com.au /telco/articles/wdm_links.html   (1496 words)

  
 What is DWDM? - A Word Definition From the Webopedia Computer Dictionary
Short for Dense Wavelength Division Multiplexing, an optical technology used to increase bandwidth over existing fiber optic backbones.
DWDM works by combining and transmitting multiple signals simultaneously at different wavelengths on the same fiber.
So, if you were to multiplex eight OC -48 signals into one fiber, you would increase the carrying capacity of that fiber from 2.5 Gb/s to 20 Gb/s.
www.webopedia.com /TERM/D/DWDM.html   (200 words)

  
 IEC: Dense Wavelength Division Multiplexing (DWDM)
Dense wavelength division multiplexing (DWDM) is a fiber-optic transmission technique that employs light wavelengths to transmit data parallel-by-bit or serial-by-character.
Consider these and other benefits of our FREE registration, or register by clicking here.
www.iec.org /online/tutorials/dwdm   (127 words)

  
 Wavelength Division Multiplexing
These circuits may enable imaging at more than 20 bits of dynamic range, where the current state of the art (around 10 bits) is over an order of magnitude lower.
The ability to bring signals directly from the detectors to the readouts in a highly parallel manner without initially going through row-column multiplexers will allow for high frame rates concurrently with high-resolution images.
www.darpa.mil /mto/visa   (183 words)

  
 Lightwave Magazine news covering fiber optics, fiber optic products, fiberoptic cable, fiber optic testing, optical fibre & more
May 1, 2006 Bonn, Germany and San Jose, CA -- T-Online, a division of Deutsche Telekom's T-Com subsidiary, announced...
April 27, 2006 Murrieta, CA -- Nuphoton Technologies, a provider of fiber-optic amplifiers and fiber lasers, has released its NP2000-XT, an Erbium doped fiber amplifier (EDFA) that supports an extended operating temperature range of - 40 to + 85°C - beyond the Telecordia specification...
April 27, 2006 San Jose, CA -- Micrel has introduced the SY88353BL, which the company calls a low power, high-performance, 3.2 Gbit/sec limiting post amplifier optimized for WDM systems; the device is also suitable for Gigabit Ethernet, 1X and 2X Fiber Channel, and OC-3/STM-1 through...
lw.pennnet.com /home.cfm   (821 words)

  
 Pooling Technologies - Wavelength Division Multiplexing (DWDM) technology
That's what Centerpoint Broadband Technologies did 10 days ago, when it announced an all-stock deal to acquire Zaffire, a company with sturdy Dense Wavelength Division Multiplexing (DWDM) technology, but wobbly financial legs.
Centerpoint's flagship Subcarrier Multiplexing-powered LENS 1220 packs 20 gigabits per second of data onto a single wavelength, and can handle a mix-or-match bag of Synchronous Optical Network, IP or Asynchronous Transfer Mode technologies; LENS stands for Centerpoint's Lightwave Efficient Network Solution.
DWDM combines multiple wavelengths of light onto a single fiber.
www.eweek.com /article2/0,1759,1240580,00.asp   (1246 words)

  
 CWDM ( Wavelength-division Multiplexing, WDM, Coarse Wavelength Division Multiplexing, Wave Division Multiplexing, and Coarse Wave Division Multiplexing) Definition
CWDM (Wavelength-division Multiplexing, WDM, Coarse Wavelength Division Multiplexing, Wave Division Multiplexing, and Coarse Wave Division Multiplexing) Definition
Metrobility’s Ethernet over Coarse Wave Division Multiplexing (EoCWDM) solution combines passive optical CWDM technology with Radiance Gigabit Ethernet line cards and superior network element management through NetBeacon Element Manager.
An optical transmission method that is used for shorter distances than dense WDM (DWDM).
www.bitpipe.com /tlist/CWDM.html   (262 words)

  
 CWDM (coarse wavelength division multiplexing)
The use of uncooled lasers reduces cost, compared with dense wavelength division multiplexing, which uses cooled lasers.
A type of wave division multiplexing in which uncooled lasers are used to overlay optical light channels in a pipe.
But CWDM can only scale up to five or six wavelengths, vendors and analysts say.
www.networkworld.com /details/479.html?def   (558 words)

  
 Wavelength Division Multiplexing - Compare Prices, Reviews and Buy at NexTag - Price - Review
Wavelength Division Multiplexing - Compare Prices, Reviews and Buy at NexTag - Price - Review
Extreme Networks BLACKDIAMOND WDMI WAVLGTH DIVISION MULITPLEX MOD
Last updated: May 01, 2006 22:56 -841065916 v1x5 810341671
www.nextag.com /wavelength-division-multiplexing/search-html   (40 words)

  
 WDM, DWDM,CWDM Wave Division Multiplexing, Course Wave Division Multiplexing
This example shows how multiple channels of ESCON can be converted with the Fiber Driver-LD ESCON Solution into a single wavelength before wave division multiplexing, allowing up to 64 ESCON channels on a 16 wavelength CWDM system, or hundreds of ESCON channels using DWDM.
Multiplexing is the process of combining several data streams operating at unique wavelengths on several fibers onto a single fiber "trunk".
Sub-rate Multiplexing is the process of placing several data streams onto a single wavelength, in an effort to further increase the number of data streams in a WDM system.
www.atekcommunications.com /wdm.htm   (1069 words)

  
 NASA Tech Briefs: Adaptive multiplexing for free-space optical communication
"Laser-based adaptive wavelength division multiplexing and code division multiplexing" (LAWDM-CDM) is the name of a method that has been proposed to increase security, signal-to-- noise ratios (SNRs), redundancy, and adaptability in free-space optical communications.
Wavelength- and code-division multiplexing would be utilized for security and improved performance.
The figure illustrates an example of a simple system that would utilize a combination of wavelength-division multiplexing and time-spread code-division multiplexing to increase security.
www.findarticles.com /p/articles/mi_qa3957/is_200204/ai_n9070976   (633 words)

  
 Time division multiplexing expansion subsystem (US6151336)
A modular time division multiplexing expansion subsystem for transmitting a plurality of incoming information-bearing signals between a first station and a second station over a single wavelength channel of a wavelength division optical fiber transmission medium, said subsystem comprising
The present invention provides an expansion subsystem for dense wavelength division multiplexing systems allowing for the time division multiplexed transmission of lower speed information-bearing signals without regard to data rate or transmission format.
The subsystem includes a transmitting station having data buffers, encoders for encoding a unique identification code from a channel identification generator, data scramblers, a multiplexing clock and a time division multiplexing unit, and a receiving station generally the mirror image of the transmitting station.
www.delphion.com /details?pn=US06151336__   (823 words)

  
 65
This project will combine code division multiplexing with wavelength division multiplexing to produce a large number of communication channels that support bursty, asynchronous, concurrent communications.
During Phase I, a set of 32 wavelength/time matrix codes was explored by means of design studies, simulations, and subscale experiments on a fiber optic link.
The propagation of the codes over a 476 km optical link of the National Transparent Optical Network was measured in conjunction with the Lawrence Livermore National Laboratory, and means of modulating the laser sources for coding were measured in conjunction with the Caltech/Jet Propulsion Laboratory.
www.er.doe.gov /sbir/awards_abstracts/sbirsttr/cycle19/phase2/065.htm   (242 words)

  
 WDM
Wave division multiplexing (WDM) or Dense wavelength division multiplexing (DWDM) is a technology that puts data from different sources together on an optical fiber, with each signal carried on its own separate light wavelength
WDM or DWDM is a new technology in multiplexing data.
Although for now, TDM is the primary approach in today’s network, WDM is expected to be the central technology in the all-optical networks of the future.
cops.uwf.edu /eme3402/week12/WDM.htm   (200 words)

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