Dense wavelength division multiplexing (DWDM) employs multiple light wavelengths to transmit signals over a single optical fiber. Today, DWDM is a crucial component of optical networks because it maximizes the use of installed fiber cable and allows new services to be quickly and easily provisioned over existing infrastructure. Flexible add/drop modules allow individual channels to be dropped and inserted along a route. An open-architecture system allows a variety of devices to be connected, including SONET terminals, ATM switches, and IP routers. This approach to network engineering provides flexible and scalable growth.

Whitepapers

What is Wavelength Division Multiplexing (WDM)? This document presents the optical technology of Wavelength Division Multiplexing (WDM).

Resources

	Comparing Metro WDM Systems: Unidirectional vs. Bidirectional Implementations This paper tries to shed some light on unidirectional vs. bidirectional implementations, explaining the differences and comparing pros and cons for the two alternative approaches.
	Introduction to DWDM for Metropolitan Area Networks This document provides background on why dense wavelength division multiplexing (DWDM) is an important innovation in optical networks and what benefits it can provide for Metropolitan Area Networks.

Optical Products Supporting DWDM
To find out more about the Cisco optical products that support DWDM, click on the following links:

	Cisco ONS 15808 DWDM Platform
	Cisco ONS 15800 DWDM Platform
	Cisco ONS 15540 Extended Services Platform
	Cisco ONS 15454 Optical Transport Platform
	Cisco ONS 15327 Metro Edge Optical Transport Platform
	Cisco ONS 15200 Metro DWDM Family
	Cisco Metro 1500 series, MAN DWDM