An optically powered fiber optic sensor system having a control end sending, with a laser diode or light-emitting diode, optical power and a clock signal exclusively through an optic fiber to a sensing end having sensors, a clock signal picking-off circuit, a return signal light-emitting diode, and needed...http://www.google.de/patents/US4857727?utm_source=gb-gplus-sharePatent US4857727 - Optically powered remote sensors with timing discrimination
