Do You Know All These Terminologies of WDM Technology ?

As an unprecedented opportunity to dramatically increase the bandwidth capacity, WDM (Wavelength Division Multiplexing) technology is an ideal solution to get more bandwidth and lower cost in nowaday telecommunications networks. By virtue of fame, WDM becomes a household word now. Yet, most of the time, we only know what is "WDM" but do not really know WDM technology. Actually, there are various of terminologies used in WDM that are always a headache for us. Now, let's see what are they.

1.Basic Terminologies of WDM
2.WDM Transmission System
3.Network Topologies
4.Filtration Technologies Applied to WDM
5.WDM Equipment
6.Ports on WDM Equipment
7.Parameters of WDM Systems
8.New Network Technologies Based on WDM

WDM (Wavelength Division Multiplexing)
A technology that multiplexes a number of optical carrier signals onto a single optical fiber by using different optical wavelengths (i.e., colors) of laser light. It breaks white light passing through fiber optic cable into all the colors of the spectrum, much like light passed through a prism creates a rainbow. Every wavelength carries an individual signal that does not interfere with the other wavelengths.

1.CWDM (Coarse Wavelength Division Multiplexing)
CWDM is a specific WDM technology defined by the ITU (International Telecommunication Union) in ITU-T G.694.2 spectral grids, using the wavelengths from 1270 nm to 1610 nm within a 20nm channel spacing. It is a technology of choice for cost efficiently transporting large amounts of data traffic in telecoms or enterprise networks.

2.DWDM (Dense Wavelength Division Multiplexing)
DWDM is a specific WDM technology also defined by the ITU but in ITU-T G.694.1 spectral grids. The grid is specified as frequency in THz, anchored at 193.1 THz, with a variety of specified channel spacing from 12.5 GHz to 200 GHz, among which 100 GHz is common. In practice, DWDM frequency is usually converted to wavelength. DWDM typically has the capability to transport up to 80 channels (wavelengths) in what is known as the Conventional band (C-band) spectrum, with all 80 channels in the 1550 nm region.