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 for remotely powering 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.

We propose the integration of power over fiber in the next generation 5G radio access network front-haul solutions based on spatial division multiplexing with multicore fibers. The different architectures in both shared-and dedicated-core scenarios for power over fiber delivery and data signals are described. The maximum power to be delivered depending on the efficiencies of the different components is addressed as well as the limits of the delivered energy to avoid fiber fuse and non-linear effects. It is shown how those limits depend on high power laser linewidth, fiber attenuation, link length and fiber core effective area. The impairments related to non-linear effects, multicore fiber crosstalk and temperature are also theoretically analyzed. Experiments show there is no degradation of signal quality for feeding powers of several hundreds of milliwatts for both scenarios in 4-core multicore fibers. This study helps in designing future power by light delivery solutions in Radio over Fiber systems with multicore fibers.

We propose using power-over-fiber (PoF) in some part of future 5G cellular solutions based on radio access networks considering currently installed front-haul solutions with single mode fiber to optically power communication systems for 5G new radio (NR) data transmission. Simulations addressing design parameters are presented. Radio-over-fiber (RoF) transmission over single mode fiber (SMF) is experimentally implemented and tested for link lengths ranging from 100 m up to 10 km with injected PoF signals up to 2 W. 64QAM, 16QAM and QPSK data traffic of 100 MHz bandwidth are transmitted simultaneously with the PoF signal showing an EVM compliant with 5G NR standard, and up to 0.5 W for 256QAM. EVM of 4.3% is achieved with RF signal of 20 GHz and QPSK modulation format in coexistence with delivering 870 mW of optical power to a photovoltaic cell (PV) after 10 km-long SMF link. Using PoF technology to optically powering remote units and Internet-of-Things (IoT) solutions based on RoF links is also discussed.

A novel self-referencing fiber optic intensity sensor based on bending losses of a partially polished polymer optical fiber (POF) coupler is presented. The coupling ratio (K) depends on the external liquid in which the sensor is immersed. It is possible to distinguish between different liquids and to detect their presence. Experimental results for the most usual liquids found in industry, like water and oil, are given. K value increases up to 10% from the nominal value depending on the liquid. Sensor temperature dependence has also been studied for a range from 25 °C (environmental condition) to 50 °C. Any sector requiring liquid level measurements in flammable atmospheres can benefit from this intrinsically safe technology.

Abstract:A new scalable self-referencing sensor network with low insertion losses implemented in Coarse Wavelength Division Multiplexing (CWDM) technology is reported. It allows obtaining remote self-referenced measurements with a full-duplex fibre downlead up to 35 km long, with no need for optical amplification. Fibre Bragg gratings (FBG) are used in order to achieve a reflective configuration, thus increasing the sensitivity of the optical transducers. Low-cost off-the-shelf devices in CWDM technology can be used to implement and scale the network. Ring resonator (RR) based incoherent interferometers at the measuring points are used as selfreferencing technique. A theoretical analysis of power budget of the topology is reported, with a comparison between the proposed network and a conventional star topology. Finally, the new configuration has been experimentally demonstrated.