Wavelength division multiplexing (WDM) is a technology for increasing the transmission capacity of optical fiber communications by sending multiple data channels simultaneously through a single fiber, each on a different wavelength of light. This technique enables bidirectional communications over a. Wavelength division multiplexing is an analog technique. It is the most important and most popular method to increase the capacity of an optical fiber. The most common five techniques are FDM, TDM, WDM, CDM and SDM. Tailored for professionals sourcing solutions from CommMesh, it.