DWDM/ROADM – WDM is a cost-effective, flexible, scalable technology to increase the capacity of a fiber optic network. Instead of transmitting on a fiber strand a single signal/wavelength, DWDM transmits multiple signals, each with a different wavelength on a fiber strand. Each wavelength remains a separate data signal, at any bit rate with any protocol, unaffected by other wavelength signals on the fiber strand. Reconfigurable optical add/drop multiplexers (ROADM) adds the ability to remotely switch DWDM wavelengths. ROADMs are used for networks that change frequently.