CWDM Explained

CWDM Explained

CWDM is an acronym for coarse wavelength division multiplexing, which is a variation of WDM, or wavelength division multiplexing. It’s a optical transmission system that is utilized for short distances, whereas dense wavelength division multiplexing (DWDM) is used for longer distances.

How It Works

CWDM offers eight channels and eight wavelengths, ranging from 1470 nm up to 1610 nm. There is a spacing of 20 nm between each channel. In other words, CWM transmits fewer channels by way of wider spacing set between each channel at distances that can reach up to 60 km. The wider spacing (20 nm as compared to 1.6 nm of DWDM) tolerates much higher temperatures and much greater fluctuations in temperature than DWDM.

Types of CWDM Optical Devices

There are three basic types of CWDM optical devices, which include 4-, 8-, and 16- channel mux/demux modules; or, as an add/drop module.

Distance of Transmission

While DWDM multiplexing systems can transmit over longer distances because of the tightly packed wavelengths, CWDM systems are limited in their transmission capabilities. Typically, CWDM has the ability to transmit data up to a maximum of 100 miles.

Benefits of CWDM

Coarse wavelength division multiplexing is a low-cost way to maximize the capacity of existing fiber optic cables by decreasing the channel spacing between wavelengths; its much less expensive than DWDM, and a configuration isn’t necessary. CWDM has the ability to boost the bandwidth of an existing fiber infrastructure, as well as ease the exhaustion of the fiber.

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