a b s t r a c tSome smart windows make use of suspended particle devices (SPDs) which are made of charged rodshape particles that change their orientation in an applied electric field, thereby allowing transmittance control. In this work, the electro-optical behaviour of a commercial SPD is analyzed. Impedance analysis shows characteristics similar to those of a Randles circuit, and a modified equivalent circuit is proposed and experimentally validated. Intermediate levels of transmittance are obtained using a customized field programmable gate array (FPGA)-based electrical circuit. Finally, measurements are taken to check the applicability of the SPD device and control system in smart glazing or photonic applications.
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.
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 3.15mW. 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.
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