Optical data bus technologies for automotive applications

This paper deals with state of the art and next-decade technologies for optical data buses in automotive applications. Nowadays, optical data buses in automotive applications are almost exclusively used in the infotainment domain, MOST (Media Oriented System Transport). Current data rates are in the order of 20 Mbit/s. Consequently, the use of LEDs and polymer optical fibers (POF) is sufficient. The next generation of these optical buses has to operate at about 150 Mbit/s. Therefore, the LED/POF solution has reached the uttermost limit of operation. For higher data rates, alternative solutions have to be found: The LED as transmitter has to be replaced by a vertical surface emitting laser (VCSEL), and plastic fiber (POF) will have to be substituted by polymer-cladded silica (PCS) fiber. Due to the inherent fact that, as a result, the fiber diameter is reduced, the detector area of the well-known Silicon photo diodes can also be reduced greatly. As a consequence, data rates can be extended into the Gbit/s-region. This situation then enables us to use the system for sensor applications as well, including safety-relevant operations like drive by wire, break by wire and engine management, and may at last lead in the coming decades to autonomous driving.