Injection molding of a WDM system for POF communication

Polymer Optical Fibers (POFs) possess some advantages compared to copper and glass fibers. Primarily, POFs are inexpensive, space saving, easy to handle, and not susceptible to electromagnetic interference. Therefore, POFs are a reasonable alternative in short distance data communication. Due to their specific advantages POFs are applied in a wide number of applications. The main applications include automotive communication systems and in-house-networks. Currently, only one channel is used for data transmission, which limits the bandwidth. To improve the data transmission rate over POF, the Wavelength Division Multiplexing (WDM) technique is used. Therefore an integrated Multiplexer (MUX) and Demultiplexer (DEMUX) are designed and developed in order to use multiple channels. To make the elements available to a broader market, a cost-effective mass production of MUX and DEMUX is needed. Injection molding is the only technology that allows this. However, designing the elements with regard to injection molding leads to some inherent challenges. The microstructure of an optical grating and the thick-walled 3D molded parts both result in high demands on the injection molding process. This also requires a complex machining of the molding tool. Therefore, different experiments are done to optimize the process parameter, find the best molding material, and find a suitable machining method for the molding tool. In the paper, the process steps and also the realized solutions are described.