Multiplexer products combine several data signals into one for transporting over a single fiber. Demulitplexers separate the signals at the other end. Each signal is at a different wavelength. Wavelength division multiplexing (WDM) greatly increases the capacity of systems. JDSU offers fused fiber or thin film filter WDMs for specific wavelengths or bands of wavelengths for applications from long haul to FTTP (fiber to the premise) applications. These components can be integrated into modules to meet customer requirements. Arrayed waveguide gratings (AWGs) can offer a compact, cost-effective alternative for applications with higher channel counts, such as metro core and long haul. Voltage controlled tunable filters allow for selection of wavelength from across C or L band.