Holl, S.; Haupt, M.; Fischer, U.H.P., "Injection molding of a WDM system for POF communication," Electronic Components and Technology Conference (ECTC), 2013 IEEE 63rd , vol., no., pp.2292,2297, 28-31 May 2013 Injection Molding of a WDM System for POF Communication S. Höll*, M.Haupt*, U.H.P. Fischer* * Harz University of Applied Sciences, Friedrichstr. 57-59, 38855 Wernigerode, Germany Phone: +49-(0)3943-659 825 Fax: +49-(0)3943-659 5825, Email: shoell@hs-harz.de Abstract 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. Introduction Polymer Optical Fibers (POF) are used in various fields of applications. The core material consists of PMMA (polymethylmethacrylate), while the cover is made of fluorinated PMMA (fig.1). The whole fiber has a diameter of 1 mm. POFs are used for optical data transmission based on the same principle as glass fiber. As a communication medium they offer a couple of advantages related to other data communication systems such as copper cables, glass fibers and wireless systems, and have great potential to replace them in different applications. Namely, in comparison with glass fibres (GOF), POFs have the advantage of easy and economical processing and are more flexible for optical connections [1]. However, one advantage of using glass fibres is their low attenuation, which is below 0,2 db/km in the infrared range. The larger core diameter of POFs leads to higher mode dispersion and thus to higher attenuation across the electromagnetic spectrum. This increased attenuation leaves only one remaining transmission window, namely the visible spectrum of light (400 – 700 nm). Hence, POFs are best suited for the use in short distance data communication. Here, POFs can outperform the current standard of copper cable as communication medium. On the one hand, they feature lower weight and space. On the other hand, POFs are not susceptible to electromagnetic interference. [2-3]. Also in comparison to wireless communication POFs offer two solutions to problems in the wireless domain. Firstly, like any radio frequency transmission, wireless networking signals are subject to a wide variety of interference, as well as complex propagation effects, which are beyond the control of the network administrator. Secondly, another main disadvantage of wireless communication is the susceptibility to unwanted access to the transmitted data by third parties. Hence, it is not usable for secure transmission of sensitive information. For these reasons, POFs are already used in various application domains, for example in the automotive sector and for in-house communication. In the area of automotive multimedia applications in the passenger compartment POFs have successfully replaced copper as transmission medium, mainly because of the huge weight reduction. It was first introduced by BMW in the 7er series in 2001. Since then not only high-class cars but also models targeted at the mass-market were equipped with POFs [4]. As of now, one limitation to the use of POFs in cars remains. The POF has a maximum operating temperature of 85 °C, which makes it impossible to use the fibres near the engine compartment [4]. However, this problem might be solved in the foreseeable future, which would allow the use of POFs as sensors for various in-car pressures or forces. Figure 1. POF overview related to other fibers.