Wavelength division multiplexing is divided into

Wavelength Division Multiplexing (WDM) can be subdivided into Coarse WDM (CWDM) and Dense WDM (DWDM). Coarse Wavelength Division Multiplexing (CWDM)CWDM uses fewer channels with wider spacing, typically 20 nm apart, covering a spectral range from 1270 nm to 1610 nm. It is designed for short-range communications, such as metro networks or campus links, where spectral efficiency is less critical.

CWD

M is cost-effective and compact, making it suitable for applications where the number of channels is limited and lower implementation cost is a priority. Dense Wavelength Division Multiplexing (DWDM)DWDM supports many more channels with tighter wavelength spacing, ranging from 0. 2 nm to 1.

2 nm, typically within the C-band (1530–1565 nm) and L-band (1565–1625 nm). This allows over 40 channels on a single fiber, making it ideal for long-haul and high-capacity networks, including carrier backbones and data center interconnects.

DWD

M systems often require optical amplifiers and dispersion compensation to maintain signal quality over long distances.

While DWD

M is more expensive than CWDM, it provides higher spectral efficiency and greater total bandwidth. SummaryCWDM: Sparse channel spacing, fewer channels, lower cost, short-range applications.

DWD

M: Dense channel spacing, many channels, higher cost, long-haul and high-capacity applications.

Both CWDM and DWD

M use multiplexers (MUX) and demultiplexers (DEMUX) to combine and separate optical signals of different wavelengths, enabling multiple data streams to travel simultaneously over a single fiber without interference.