Concept: How to Increase The Bandwidth Of Fiber Optics
In the “realm” of acronyms that sometimes seems to define our industry, two terms – Coarse Wave Division Multiplexing and Dense Wave Division Multiplexing have recently become top of mind with service providers.
As providers densify their networks by pushing fiber deeper and adding small cells to meet the increased growth in demand for speed and capacity.
Coarse Wave Division Multiplexing (CWDM) and Dense Wave Division Multiplexing (DWDM) offer two effective ways to increase the bandwidth of fiber by combining optical signals of different wavelengths on one fiber strand.
It’s a practical, proven solution; however, which WDM option is the best choice for your network? Whether coarse or dense, WDM technology is ideal for making the most out of new and existing fiber deployments.
Providers implement WDM by adding coarse or dense modules to their headend or hub locations, after considering the key differences between the two.
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CWDM modules increase the amount of bandwidth a fiber optic system can carry by transmitting multiple signals at various wavelengths along the fiber optic cables. CWDM can typically support up to 18 different wavelength channels on one strand of fiber.
DWDM modules also put data from different sources together on a fiber optic cable, and further increase system bandwidth and capacity by using closely spaced wavelengths to carry multiple signals on the same cable.
DWDM can typically support up to 48 wavelength channels on one strand of fiber.
Functions of Coarse Wave Division Multiplexing And Dense Wave Division Multiplexing
So, in terms of function, CWDM and DWDM are very similar; however, they differ in a couple of ways. DWDM is typically more expensive than CWDM not only because of the capacity difference, but it requires operators to install temperature-controlled lasers.
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This is because of the narrowly spaced channels that must be carefully used. A more inexpensive laser without temperature control might drift in wavelength and interfere with another DWDM channel.
While cost alone might favor CWDM, another benefit to using DWDM is that the channel band occupies a portion of the spectrum that can be amplified, where CWDM cannot.
Providers must choose or decide whether the extra cost of DWDM and the lasers is offset by the benefit of a 150 percent capacity advantage and the ability to amplify.