What are the main differences between WDM, CWDM & DWDM applications?
In most cases, WDM is the most cost effective solution to fiber congestion allowing for 2 to 1 or 3 to 1 fiber gains combining 1310nm, 1550nm, & 1490nm wavelengths on a single fiber. In the event that more channels are required to expand the capacity of the existing fiber infrastructure, CWDM allows for a cost effective solution for short fiber spans. With the 20nm spacing, CWDM can be implemented inexpensively gaining up to 18 to 1 capacity on an existing fiber. With the current loss characteristics of fiber optic signals at the 1310nm and 1490nm wavelength windows, WDM and CWDM applications are better suited for shorter fiber spans. Where high capacity or long span lengths are required, the DWDM solution is the preferred method for gaining fiber capacity. With its high-tolerance lasers optimized in the 1550nm window (for lower loss), the DWDM systems are an ideal solution for more demanding networks. DWDM systems can utilize and EDFA to amplify all the wavelengths in the DWDM window
