Optical data links for automotive applications

Optical data links and data bus systems are increasingly attractive in vehicles. After the successful introduction of the first systems in 1998 by Mercedes Benz, today optical data buses are common in more than 20 different vehicles. All currently used systems are based on polymethyl methacrylate (PMMA) optical fibers and red light emitting diodes (LEDs). They are limited to a temperature range below 85°C, moderate data rates below ca. 100 Mbit/s and short point-point-links. We investigated new physical layer approaches, both based on polymer fibers as well as on large core silica fibers. A system based on polymer cladded silica (PCS) fibers and vertical-cavity surface-emitting laser (VCSEL) diodes can be used up to data rates of 1 Gbit/s in all relevant installation areas of cars or trucks. In addition it allows new system architectures and new wiring concepts for the future and therefore has the potential to be the common and scalable physical layer for all future high data rate bus systems, e.g. drive-by-wire systems or video based driver assistant systems in cars and commercial vehicles.