An optically powered fibre network for heterogeneous subscribers

In optically powered networks, glass fibres are used for transmitting optical communication signals as well as optical energy for electrically powered devices. Advantages over existing power delivery technologies are: immunity to electromagnetic interference, spark-free power for safety-critical applications, slim cables, simple installation and reduced maintenance cost. Applications relate to security of public spaces and buildings, down-hole exploration, medical endoscopes, and to communications in the context of remote RF antennas and passive optical networks (PON). An optically powered network can connect widely differing subscribers with low/high bandwidth requirements, asynchronous/synchronous operation, and low/high priority, e.g., energy-preserving small-bandwidth subscribers with ultra-low duty cycles and low network priority (e.g., temperature sensors) in combination with wide-bandwidth subscribers operating at large duty cycles and high priority (e.g., video conferencing). Optical energy is supplied centrally from an access point, and this results in a combined star and tree-like network topology. As a consequence, subscribers communicate with the CO only, and therefore a standard carrier sense multiple access (CSMA) protocol cannot handle the data exchange. We present optically powered subscriber hardware and demonstrate a low-energy medium-access control (LE-MAC) protocol that extends the IEEE 802 standard, allows random and scheduled medium access of subscribers, and, by quality-of-service support, efficiently uses the available resources, namely channel bandwidth and optically supplied energy.