DEVELOPMENT OF A MICRO STRUCTURED OPTICAL 3D-GRATING FOR THE USE IN WDM OVER POF COMMUNICATION

摘要

Today, data communication over Polymer Optical Fibers (POFs) is used in areas, in which the advantages of lightweight, cost-effective fibers with easy handling is required. The main applications include automotive communication systems and in-house-networks. Currently only one channel is used for data transmission, which limits the bandwidth. The only way to improve the data transmission rate is the use of more than one data channel. This method is called Wavelength Division Multiplexing (WDM) and it uses different wavelengths for data transmission over one POF. In order to establish a WDM communication link, two main components are required. At the front of the POF link a Multiplexer (MUX) bundles the light sources with different wavelengths to a single fiber. At the end of the transmission path the incoming light must be separated by a Demultiplexer (DEMUX) into the different wavelengths. In order to keep the advantage of cost-effective POFs, it is necessary to mass-produce the MUX and DEMUX component at reasonable prices. For polymers, injection molding is the only technology which achieves this goal. An optical grating on an aspheric mirror is used to separate the chromatic parts of the light in its monochromatic components. The manufacturing of such a micro structured grating leads to a complex machining of the molding tool. Because of the high numerical aperture (NA) of the POFs, it is necessary to design the elements in a 3D-approach. This results in thick-walled molded parts and poses challenges for the injection molding process. Therefore, different experiments are done to optimize the process parameter, find the best molding material, and to find a suitable machining method for this molding tool. In this paper, the process steps and also the realized solutions are described.