What Is DWDM?

Internet demand is always growing, especially the hugely popular video streaming services are increasing greatly. This provides a threat to the service provider. As the hottest topic in the telecommunication industry, DWDM offers unprecedented bandwidth which promises an effective solution to the challenges posed by the Internet growth. But what is DWDM, do you really know?

What Is DWDM?

DWDM wiki has defined it as an optical multiplexing technology. As one wavelength pattern of WDM system (the other pattern is CWDM), it stands for Dense Wavelength Division Multiplexing, which is used to increase bandwidth over existing fiber networks. This powerful technology can create multiple virtual optical fibers, so as to increase bandwidth on existing fiber optic backbones. It means that the fiber in the DWDM system can transmit multiple signals of different wavelengths simultaneously. More specifically, the incoming signals are assigned to specific wavelengths within a designated frequency band, then the signals are multiplexed to one fiber. In addition, the most commonly used grid is the 100GHz grid, which consists of a spacing of 0.8nm per channel.

After knowing what is DWDM, we need to learn DWDM architecture. A typical DWDM architecture includes a transmitter, receiver, optical amplifier, transponder, DWDM multiplexer, and demultiplexer. Transmitter and receiver are the places where the source signal comes in and then multiplexed. The optical amplifier can amplify the signals in the wavelength range, which is very important for DWDM application. The transponder is the converter of wavelength. It’s responsible for converting the client optical signal back to an electrical signal. Multiplexer first combines multiple wavelengths of different fiber to one fiber, and at the receiving end, the demultiplexer separates all wavelengths of the composite signal onto individual fibers. Commonly, channels of DWDM Mux/Demux are available in 8, 16, 40 and 96 channels. All the DWDM basics work together to enable high capacity data-flow in ultra-long distance transmission. The following figure is the DWDM working principle.


Why Use DWDM Technology?

The most obvious advantage of DWDM technology is providing the infinite transmission capacity, which would meet the increasing Internet demand. And more capacity can be added just by upgrading several types of equipment or increasing the number of lambdas on the optical fiber. Thus, the investment of DWDM technology has been reduced. Besides, DWDM technology also enjoys several other advantages, like transparency and scalability.

Transparency. Due to DWDM is a physical layer architecture, it can support Time Division Multiplex and data formats like Gigabit Ethernet, Fiber Channel with open interfaces over a physical layer.

Scalability. It’s easy to be expanded. A single fiber can be divided into many channels, thus there is no need to add extra fiber but the wavelength will be increased. All these advantages make DWDM popular in the network.

Application of DWDM

As a new technology more applications of DWDM are yet to be tapped and explored. It was first deployed on long-haul routes. And now, DWDM technology is ready for long distance telecommunication operators. Using point to point or ring topology, the capacity will be dramatically improved without deploying an extra fiber. In the future, DWDM will continue to provide higher bandwidth for the mass of data. With the development of technology, the system capacity will grow.


As for the question what is DWDM, I believe you have a good understanding of it. This powerful technology is related closely with current industry advancements trend. Now, service providers are faced with a sharp growth in demand for network capacity, DWDM is the best solution. With DWDM technology, the transmission work is no longer limited by the speed of available equipment, because it provides the high bandwidth without limit. We believe, DWDM will shine in the network world.

Author: Feisu

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