DWDM Increase Bandwidth
Dense Wavelength Division Multiplexing or DWDM is one of the two methods used for wavelength division multiplexing in fiber optic communications, the other being coarse wavelength division multiplexing or CWDM. Wavelength division multiplexing is a technique which multiplexes several optical signals onto a fiber optic cable by using different wavelengths of the light.
Comparison of DWDM and CWDM Systems Both CWDM and DWDM provide higher bandwidth by consuming lesser number of cores of fiber optic cable and fewer ports of communication
equipment. The higher bandwidth is a result of transmitting multiple streams of data on a single fiber at the same time. All of the channels being transmitted accumulate to a consolidated bandwidth which is much higher than the normal data transmission methods which use single transmit and receive channels. CWDM and DWDM use similar techniques for data transmission, the major difference being the channel spacing. In CWDM the channel spacing is wider than the DWDM. As the name suggest, the number of channels in DWDM are much denser than that of CWDM. The more the channels, the more the bandwidth. DWDM transceivers today are primarily available as SFP, XFP and SFP+ form-factors providing 1 Gbps and 10 Gbps bandwidths respectively. The channel spacing is denser in SFP+ DWDM transceivers as compared to SFP DWDM transceivers. DWDM has the capability to carry 40 Gbps, 100 Gbps and 400 Gbps data in a single core of fiber optic cable. DWDM transceivers require very delicate technology and accurate wavelength splitting as the channel spacing is very small. This results in the DWDM transceivers to be higher in cost than the CWDM transceivers.