Optical multiplexing technologies for access-area applications

This paper describes optical multiplexing technologies expected to be applied to access-area networks. First, these technologies are broadly categorized into wavelength-division multiplexing (WDM) and optical code-division multiple access (OCDMA), and possible variants are described in a comparison to time-division multiple access (TDMA). Next, their typical performances reported so far are overviewed in relation to the light sources utilized. While it is well known that WDM/OCDMA exhibits higher performance with laser sources, it is pointed that WDM/OCDMA with incoherent light sources are interesting alternatives for access-area applications. Two multiplexing methods that use incoherent light sources are introduced in more detail; one is spectrum-sliced WDM and the other is coherence-multiplexed CDMA. After the introduction of transmission experiments, their performance limitations are discussed.