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DWDM Systems

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In this 'Viewpoint' we take a look at the world of Wavelength-division multiplexing (WDM) and particularly Dense Wavelength Division multiplexing (DWDM), a term usually applied to fibre optic communications. It is a technology that allows multiple optical signals to reside on the same optical fibre. These signals are produced by lasers of differing wavelengths (colours). DWDM makes efficient use of fibre cabling by increasing its capacity and in effect making it appear as if multiple fibres are in use where only one really is.

Let's take a specific example – assume we have a 10Gbps link between 2 locations running over a pair of fibres. With DWDM technology we could increase this to 80 x 10Gbps links running over the same fibre pair. Thus increasing the capacity 80 fold without any additional infrastructure.

Other benefits of DWDM technology are:-

  • Enables rapid expansion of network capacity
  • It saves time, cost and effort of installing new fibre infrastructure
  • It's transparent in operation so no upgrade of existing equipment is necessary

It appears that some are a little confused by the apparent differences between CWDM (Coarse Wavelength Division Multiplexing) & DWDM, but it really comes down to capacity and application, i.e.:

  • CWDM typically provides 8 channels and is used widely in Enterprises, whereas
  • DWDM provides up to 80 channels so is commonly used by Carriers.

General Advantages of CWDM and DWDM are:

  • Easy multiplication of the capacity of a fibre link by transmitting different data streams on different parts of light spectrum
  • Enhanced usage of existing fibres – and therefore reduced investment in civil engineering works for installation of further fibre optic cables
  • 100% protocol transparent – and therefore no impact on data streams and no relevant additional latency
  • Simple and scalable solution – add new WDM channels required and only pay for the bandwidth which is actually needed
  • 100% traffic seperation & up to 80 wavelengths on one fibre pair.

By using WDM technologies, fibre optic capacities can be elegantly and cost-efficiently multiplied. A few years ago, expensive WDM optics and complex installation processes prohibited wide-spread commercial use of WDM systems for regional and local fibre optic connections. These limitations are overcome by the current generation of WDM systems. Lanode is a distributor for the Pan-Dacom SPEED-CARRIER WDM System. The SPEED-CARRIER WDM series grows flexibly along the network requirements – from simple n x E1 system up to redundant multi 10 Gigabit nodes. Developed and manufactured in Germany, the Pan Dacom SPEED-CARRIER WDM System offers the highest standards of quality, reliability, outstanding flexibility and cost efficiency. You can find out more here.....