LED as transmitter and receiver in POF - based bidirectional communication systems

Light emitting diodes (LED) can be used not only as light sources but also as light detectors similar to photodiodes. This property will here be used to extend a commercial plastic optical fiber (POF) based one directional communication system to a bidirectional communication system with the possibility to work in half duplex mode. It will be shown that this approach can generally simplify essentially the optical setup of bidirectional optical communication systems. Furthermore, the transmission of light energy via POF will be utilized to provide a node in an optical communication system with electrical energy. Such power over optical fiber system makes a node in the communication system independent of the access to external electrical power supply. The system performance will be discussed in dependence of the electro optical properties of POF based communication systems.