Design and realization of a power-over-fiber sensor system for internet of things

In this paper, a sensor system for the internet of things under extreme environment is developed based on the power-over-fiber technique. Via this technique, high laser power is transmitted over fiber link, and is converted into electric energy by photovoltaic power converter (PPC) at the end of the link. As the fiber is inherently immune to electromagnetic interference, the converted electric energy drives sensor nodes safely. To improve the power-supply efficiency, the impedance-matching tracking method is proposed to enable the maximum electric power output of the PPC for any load. Based on this method, a smart power manager is realized to store the electric energy and an appropriate voltage is set to drive the sensor nodes. Moreover, a simple and reliable communication protocol is proposed to adjust the working mode of the sensor nodes. In this way, the power consumption of nodes is reduced and the applicable ability of the system is enhanced. In the power-over-fiber sensor system constructed in this paper, the maximum electric energy output of PPC is 555 mW when the incident optical power is 1.5 W, and the effective optical-electric conversion efficiency is 37%. The system can sample, process and display sensing information stably over a distance of 2 km. Such a system affords a novel solution to realize the internet of things safely and reliably. ©, 2015, Board of Optronics Lasers. All right reserved.