
The functionality of DWDM resembles to the one of CWDM. Unlike to CWDM technology, the channel spacing for DWDM is 0.8/0.4 nm (100 GHz/50 GHz grid). This small channel spacing allows to transmit simultaneously much more information.Currently a restriction on wavelengths between 1530 nm and 1625 nm exists which corresponds to the C and L band. In this connection DWDM
wavelengths from DWDM technology is more expensive compared to CWDM caused by the need of more sophisticated transceivers.
