DWDM is a subset of wavelength-division multiplexing (WDM) that typically uses the spectrum band within 1530nm and 1625nm, or more commonly the C-band and L-band, to input 40, 88, 96, or even 160 wavelengths, or channels, onto a single strand of fiber optic cable. According to Dell'Oro, DWDM is projected to achieve a compound annual growth rate of 3%, reaching $18 billion by 2026. This guide delves into the principles, types, applications, and future trends of WDM. Tailored for professionals sourcing solutions from CommMesh, it. Coarse Wavelength-Division Multiplexing (CWDM), the first generation of WDM in optical communication, offers up to 18 channels. WDM allows communication in both the directions in the fiber cable.