Potential niches for Power-over-Fiber (PoF) technique can be found in hazardous areas that require controlling unauthorized access to risk areas and integration of multiple sensors, in scenarios avoiding electromagnetic interference, and the presence of ignition factors. This paper develops a PoF system that provides galvanic isolation between two ends of a fiber to remotely power a proximity sensor as a proof of concept of the proposed technology. We analyze scalability issues for remotely powering multiple sensors in a specific application for hazardous environment. The maximum number of remote sensors that can be optically powered and the limiting factors are also studied; considering different types of multimode optical fibers, span lengths and wavelengths. We finally address the fiber mode field diameter effect as a factor that limits the maximum power to be injected into the fiber. This analysis shows the advantages of using Step-index versus Graded-index fibers.

Using bundles of multimode optical fibers (MMF) as part of the 5G centralized radio access networks front-haul solutions for optically powering of low power consumption Remote Radio Heads (RRH) is proposed and experimentally demonstrated with 100 m of 200 μm core diameter MMF. From the 34.85 W electrical power provided to the system, 1.748 W are delivered to the load, giving an overall 5% efficiency, being the temperature controller of the High Power Lasers the most critical element. If intermediates results are considered, the efficiency from input optical power to electrical power after the PV cells is 43.4%. The RRH manages 2.34 W for control, battery charge, communications and the load operation. The system includes a low power bidirectional control channel that provides the capability of enabling different sleep modes and sending information about the status of the battery and sensing elements at RRH. The RRH has a minimum power consumption of 3.15 mW. Optimized design of different elements of the system are included. The system is tested by feeding a RF power amplifier at the RRH; providing a stable power supply and EVM performance below 17.8% with QPSK on a 20 GHz RF carrier.

We report the experimental results on a new infrared fiber-optic pyrometer for very localized and high-speed temperature measurements ranging from 170 to 530 °C using low-noise photodetectors and high-gain transimpedance amplifiers with a single gain mode in the whole temperature range. We also report a shutter based on an optical fiber switch which is optically powered to provide a reference signal in an optical fiber pyrometer measuring from 200 to 550 °C. The tests show the potential of remotely powering via optical means a 300 mW power-hungry optical switch at a distance of 100 m, avoiding any electromagnetic interference close to the measuring point.

In this work, a combination of a multiplexer and a variable optical attenuator in the same device (VMUX) for use in Polymer Optical Fiber is proposed. Polymer Dispersed Liquid Crystals (PDLC) are polarization independent, have high contrast and gray scale capability. For these reasons, PDLC cells with pixels can be used as switching elements in the device. Characterization of the PDLC has been carried out at two wavelengths. VMUX Complete switching is reached for driving voltages of 20 Vrms, with insertion losses less than 1.6 dB, attenuation larger than 31 dB, rise time less than 2.6 ms and decay time better than 12.4 ms have been obtained.