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86 PCB007 MAGAZINE I JANUARY 2021 ables the required free optical routing. The op- tical waveguides are part of separate optical layers resulting in an EOCB. [6-10] This process uses an embossing mold (shim) to hot emboss the foil structure of the wave- guide. Topas, the optical material, fills the de- formed core. After curing, the core is laminat- ed into the EOCB. A hot embossing process, which is one pos- sible way of fabrication, is based on first man- ufacturing rib waveguides, which are laminat- ed in a second step on a polymer substrate. Fi- nally, the optical layer is obtained after filling with the over-cladding. In order to meet the high temperature requirements already men- tioned, high-Tg materials such as COC or spe- cial polycarbonate can be used. An example of the European program can be seen in Figures 7 and 8. These show the Sie- mens C-Lab test vehicle, called OptoSys, fab- ricated by a collaboration of Siemens AG, In- fineon Technologies AG, ILFA Feinstleitertech- nik Gmbh, Daimler Chrysler. The EOCB is a consortium of Andus, Fraunhofer IZM Berlin, ILFA, Mikropack, OECA, Robert Bosch, Siemens and the Univer- sity of Paderborn. They are now replaced by commercial firms like Vario-Optics AG of Vil- lingen, Switzerland, and tested/qualified by Microtec GmbH laboratories [Pusch-2006]. Mi- crotec tested and reported on the EOCB perfor- mance along with failure mechanisms and fail- ure predictions. [11] This provided new informa- tion for standards and pre-qualification actions. A new opto-interconnect program has start- ed in the EU. PhoxTroT (Photonics for high- performance, low-cost and low-energy data centers, high performance computing systems, Terabit/s Optical Interconnect Technologies) is a two-year, $10 million Euro program to ex- tend the performance of optical interconnec- tions and infrastructure. Integrated Optical and Electronic Interconnect PCB Manufacturing In the UK, a large team of university and industrial companies collaborated under EP- SRC's leMRC, and OPCB, namely Universi- ty College London, (UCL) Instigator, Princi- pal Investigator and Technical Project Lead- er; the School of Engineering and Physical Sci- ences, Heriot-Watt University, Edinburgh; and Figure 6: Concept of a printed circuit board with an integrated optical layer containing optical multi-mode waveguides. [6]