DWDM Disadvantages: · High Cost: Significant investment in both initial hardware and ongoing operations. · Complexity: Requires careful planning, precise engineering, and specialized skills to manage. · Power and Space Intensive: Amplifiers and control units consume considerable. High Security: WDM provides enhanced data security. While WDM offers many advantages, it also has some drawbacks: Signal Separation: Signals must be sufficiently spaced apart in frequency to avoid interference. Coarse. Wavelength division multiplexing (WDM) uses optical multiplexing to increase the bandwidth of existing fiber optic cables without adding additional cables.