ABSTRACT
This chapter presents the operating principles of wavelength-division multiplexing (WDM) and describes the components needed for its utilisation in systems. These components range from simple devices to sophisticated tunable optical sources and wavelength filters. Multiplexer and de-multiplexer devices can be either passive or active in design. Passive designs are based on the use of a prism, diffraction grating or filter. Active designs combine passive devices with tunable filters. The chapter presents two experiments in both multiplexing/de-multiplexing of light signals from many light sources, using different techniques. WDM technology has evolved to the point that channel wavelength separations can be as small as a few nanometres, giving rise to dense wavelength division multiplexing (DWDM) systems. DWDM is a fibre-optic transmission technique that employs light wavelengths to transmit data as parallel bits or a serial string of characters. The chapter discusses the time-division multiplexing (TDM) and frequency-division multiplexing (FDM).
