January 21, 2020

WDM: Everything you Need to Know

In this blog post, we examine Wavelength Division Multiplexing and its two types: coarse wavelength division multiplexing (CWDM) and dense wavelength division multiplexing (DWDM). Together, these technologies are helping network operators save money by maximizing the bandwidth capabilities of their existing fiber optic network infrastructure.

Before we get fully into WDM, let’s first talk about its underlying basis – multiplexing. Because a large bandwidth of optical fiber is generally unlikely to be used by a single client or application, bandwidth sharing throughout multiple sources proved to be a cost-effective move for network owners. Thus, multiplexing was born. Since then, three divisions on multiplexing approaches have emerged: time division multiplexing (TDM), space division multiplexing (SDM), and wavelength division multiplexing (WDM). For the purpose of this blog, we’ll focus on WDM as it has become one of the most popular network connectivity solutions, not only for service providers and carriers, but also for Fortune 500 enterprises, government organizations and data centers.

Wavelength Division Multiplexing

Defining WDM

In layman’s terms, Wavelength Division Multiplexing is the process by which optical signals with differing wavelengths are combined for transmitting through a MUX, and then separated through a DEMUX. This technology allows multiple wavelengths/channels to be transmitted across a single fiber. WDM technology has two sub-categories that are commonly used today; these are known as CWDM and DWDM.


CWDM (Coarse Wavelength Division Multiplexing) and DWDM (Dense Wavelength Division Multiplexing) are similar because they both function by means of multiplexing. However, they are different in the way that they are comprised and defined. We’ve highlighted the key differences in the table below. 

CWDM (Coarse Wavelength Division Multiplexing) and DWDM (Dense Wavelength Division Multiplexing)

Precision Transceiver Channels

Precision Transceiver DWDM Channels and Wavelengths

The use of multiplexing has evolved the world of fiber optic networks in a significant way. From WDM to CWDM and DWDM, these variations of multiplexing are commonly used today throughout networks and systems around the world. To take full benefit of the capabilities provided by WDM, network administrators need the best in optical networking equipment.

How Precision OT Supports WDM

At Precision OT, we’ve been supporting the needs of network operators implementing WDM for years. We eat, breathe and sleep high quality networking equipment including tunable optical transceivers and the best in fiber jumpers. Unlike static transceivers, tunable transceivers enable operators to adjust to any of the standard ITU C-band 50GHz or 100GHz-spaced channels. This lets them save money on stocking the multiple active and backup static transceivers that would be necessary to receive all the different wavelengths that share a single optical fiber. For more information, check out our tunable transceivers and our TN100-series tuning boxes that can help you simplify the tuning process.

As always, all our transceivers come with a lifetime warranty and are guaranteed to be 100% NEM compatible. So, feel free to contact our expert team of engineers. We will listen to your needs and work with you to create a customized solution. Contact us!

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