Prism-Spectrometer as Demultiplexer for WDM over POF

Polymer Optical Fibres (POFs) show clear advantages compared to copper and glass fibres (GOFs). In essence, POFs are inexpensive, space-saving and not susceptible to electromagnetic interference. Thus, the usage of POFs has become a reasonable alternative in short distance data communication. Today, POFs are used in a wide number of applications due to these specific advantages. These applications include automotive communication systems and In-House-Networking. The currently used transmission technology via POF is based only on one channel (or rather on one wavelength), making the usable bandwidth the limiting factor of this technology. One potential solution to expand the usable bandwidth of POF-based systems is wavelength division multiplexing (WDM). Because of the attenuation behaviour of POF, the only transmission window is situated in the visible spectrum. The solution proposed in this paper allows the transfer of several signals on different wavelengths through a single polymeric fibre. In order to separate the transmitted signals, special separators - called demultiplexers (DEMUX) - are utilized. These DEMUX are realized by employing the principle of the prism-spectrometer. In the set-up described in this paper, the light emitted by the polymeric fibre is collimated via an off-axis parabolic mirror. Then it is led to a dispersion prism and there divided into its monochromatic parts.