Know the Difference between CWDM and DWDM

A WDM (Wavelength Division Multiplexing) is a system that uses a multiplexing (at the transmitter) and a demultiplexer (at the receiver) for the completion of the process and transmission of the signals.

The WDM is divided into three types (WDM, CWDM and DWDM) on the basis of wavelength difference among the three. The article discusses the main differences among CWDM and DWDM.

CWDM stands for Coarse Wavelength Division Multiplexing, and DWDM is the acronym for Dense Wavelength Division Multiplexing. Whether DWDM or CWDM, both are the types of WDM mechanism and have an array of differencess.

Let’s get acquainted with the chief difference between CWDM and DWDM:

• The Coarse WDM has less than 8 active wavelengths per optical fiber whereas the DWDM has more than 8 active wavelengths per optical fiber.
• The CWDM has lower capacity strength and hence is low in costs; conversely the DWDM possesses high capacity –this leads to an augmented price which is worth its qualities.
• When it comes to the difference between the distance of the two, the CWDM has short range communication because the wavelength is not amplified, and DWDM has long range communication.
• CWDM Mux and Demux systems are developed to be used in multiplexing multiple CWDM channels into one or two fibers.
• Another major difference is that DWDM systems are made for longer haul transmittal, by keeping the wavelengths closely packed. Also, a DWDM device can transmit more data over long distances and to a significantly larger run of cable with lesser interference than a comparable CWDM system which has a shorter haul transmittal.
• Furthermore, the Dense Wavelength Division Multiplying systems are capable to fit more than forty different data streams in the amount akin to that of fiber used for two data streams in a CWDM system.

Apart from all the difference there is one more and that is wavelength drift is possible in CWDM, but when it comes to the DWDM –precision lasers are needed to keep channels on the target.

Beyond being different from each other –these systems play different roles in the effective transfer of the signals, and thereby both are important enough.

Know Wave Division Multiplexing & its Working

The world knows that the physical fiber optic cabling can be a lot expensive when it comes implementing for every service separately; but this expense can be made worthy by capacity expansion using a Wave Division Multiplexing also known as WDM.

Wave Division Multiplexing technology was evolved to expand aptitude of networks that a single fiber provides. It helps because a WDM system employs a multiplexer solution at the transmitter that combines several wavelengths in concert; also in this entire process, each carries sundry signal and at the receiver –a de-multiplexer helps in splitting them apart. Both Mux and Demux are passive and thereby require no power supply.

Types of WDM

Currently there are many kinds of standardized WDM in existence. The types / kinds of Wave Division Multiplexing are:

• General WDM (that may include 980/1550 WDM and 1310/1550 WDM).
• CWDM (such as CWDM Mux and Demux module and CWDM OADM module).
• DWDM (including 50GHz, 100GHz, 200GHz DWDM mux/demux module and DWDM OADM module).

How WDM works?

The operating principle of WDM is easy and understandable. Wave Division Multiplexing is akin to the prism in the operating principle; as a prism separates white light into seven different colored rays, similarly a WDM system uses a multiplexer at the transmitter to join different signals together, and has a demultiplexer at the receiver end for splitting the signals apart. All you need is a right type of fiber optic cable, and it is possible to have a WDM device that can do both simultaneously, and can act as an optical add / drop multiplexer.

The first WDM systems (which were demonstrated with optical fiber in the early 80s) combined only two signals; however, modern systems can handle up to 160 signals. In short, WDM systems can expand the capacity of the network while accommodating many generations of technology development in optical infrastructure without having to revamp the backbone network; this quality plays in its popularity with telecommunications companies.