Multiplexing techniques are methods used to combine multiple signals into one signal over a shared medium. This allows for efficient use of resources, such as bandwidth, by enabling multiple data streams to be transmitted simultaneously. Common types of multiplexing include Time Division Multiplexing (TDM), Frequency Division Multiplexing (FDM), and Wavelength Division Multiplexing (WDM). In TDM, each signal is assigned a specific time slot, while FDM allocates different frequency bands to each signal. WDM is often used in fiber optic communications, where different light wavelengths carry separate data streams. These techniques enhance communication efficiency and capacity.