Sistemas de alimentación remota con fibras ópticas en sistemas de comunicaciones y sensado

Mención Internacional en el título de doctorThe copper conductor is the physical medium traditionally used to transport power between different points. However, in recent years a new technology called Power over Fiber (PoF) has begun to be used for the same purpose. This idea firstly developed in the 1970s by the American Telephone and Telegraph Company in the field of telephony used fiber optics to power parts of a telephone instead of traditional copper. Power over Fiber technology involves the transmission of energy using an optical fiber to feed an electronic device. In its basic configuration, it consists of an energy source, typically a high power laser (HPL), an optical fiber to transmit energy to the receiving side, and a photovoltaic converter to convert light into electrical energy. This technology has several advantages over the use of copper, due to the intrinsic properties of optical fiber such as immunity to electromagnetic interference, galvanic isolation and low weight. The use of this technology is of interest in monitoring applications in high-voltage networks requiring galvanic isolation, in nuclear power generation applications, as well as in the automotive and aviation sectors. On the other hand, a scenario of special attention regarding the application of this technology is the communications sector, due to the advantages that the synergy between the transmission of energy and data through the same physical medium can provide. For those reasons, the main objective of this research is to study and develop light-powered systems that integrate solutions with intelligence in the field of sensors and communications, ensuring optimization and management of energy consumption. This research has included one chapter for the development of applications in the sensing field and three for the analysis of Power over Fiber applications in communications scenarios, specifically in the context of 5G technology. The following is a summary of the research content by chapters. Chapter 2 presents PoF systems as an emerging technology capable of transmitting energy over short and long distances using optical fiber to power remote devices. It also discusses the main theoretical concepts and parameters related to each of the elements that compromise a PoF system. The main objective of this approach is to establish the principles that will help to understand the rest of the chapters within this research. The first sections define the elements employed by the technology, the state of the art and its characteristics. Finally, considerations and critical aspects that may limit the implementation of PoF systems are addressed. Chapter 3 discusses the state of the art of PoF technology in sensing applications. Additionally, the key aspects to consider in the development of a PoF system operating in the first window are discussed. Finally, the implementation of several sensing applications in different fields such as explosive areas, in the context of Internet of Things (IoT) and pyrometry applications are discussed. Throughout the chapter, topics such as the impact of modal field diameter and fiber fuse on the power threshold supported by the fiber, and scalability analysis for powering a sensor network with a Point-to-Multipoint configuration are also analyzed. Chapter 4 addresses the main concepts associated with 5G-NR technology and focuses on the implementation and analysis of synergistic scenarios using PoF technology in a Centralized-Radio Access Networks (C-RAN) architecture. Consumption analysis in the Remote Radio Head (RRH) is carried out to evaluate the energy requirements demanded by the 5G technology and the feasibility of using power by light. Additionally, a PoF platform is developed that implements low-power modes and remote sensing through a low-power communications channel. This functionality allows monitoring and controlling parameters of the RRH, from the Central office (CO), through a computer application implemented in Matlab. The integration of 5G and PoF (5G/PoF) technology is experimentally validated through the feeding of a RF amplifier, integrated in an Analog Radio over Fiber (ARoF) scenario. Finally, the performance of the integrated 5G/PoF system is evaluated using the EVM value as a metric. Chapter 5 addresses the impact of the main fiber optic parameters on data transmission in a 5G scenario, because of power transmission in a shared scenario (data and power multiplexing on the same optical fiber). For the analysis, different laboratory experiments and simulations are carried out in an ARoF scenario operating in millimeter wave bands, with RF carriers below 20 GHz. Additionally, the influence of the Kerr effect and the nonlinear Stimulated Raman Scattering (SRS) phenomenon on the critical frequency behavior of the system and the appearance of the power fading phenomenon are analyzed. Finally, the effect of the Relative Intensity Noise of the HPL and the effects of the coupled noise in the data channel through the SRS phenomenon are discussed. In all cases, the EVM is used as a metric for the characterization of the systems. Chapter 6 addresses a PoF solution integrated in the optical fronthaul of a 5G network in a C-RAN configuration, operating at a radio frequency of 25.5 GHz. The design employs Space Division Multiplexing (SDM) integrated with PoF over a 10 km-long multicore fiber (MCF), with the objective of powering and controlling critical elements of the RRH for remotely managing its power consumption. Agent-based intelligent control is implemented in the design. Additionally, ARoF and PoF systems are characterized and the impact of power transmission on the ARoF system is evaluated for QPSK, 16 QAM and 64 QAM modulations using the BER value as a metric. In addition, two application examples based on MCF and single mode (SMF) optical fibers are explored for the optimization of the RRH power consumption. Additionally, a technique based on Tilted Fiber Bragg Gratings (TFBG) over MCF fibers for monitoring the transmitted energy is discussed. Finally, chapters 7 and 8 summarize, in English and Spanish, the main conclusions of this research and present proposals for future work. It is important to highlight as general conclusions of this work the integration capacity of PoF systems in different application scenarios, even though the threshold power supported by the optical fiber limits its transmission capacity, being more critical in the case of multimode (MMF) fibers with a gradual refractive index profile because of its smaller modal field diameter. On the other hand, the PoF systems developed in this research are compatible with current and future infrastructures in the context of 5G technology, based on SMF and MCF fibers. This research demonstrated in practice the transmission of hundreds of milliwatts over more than 10 km, using SMF fibers. In the case of MCF the transmitted power was sufficient to implement remote control of a power amplifier from the CO. The main contributions of this research include the exploration and development of sensor applications integrating novel functionalities not covered by state-of-the-art solutions so far. The systems were tested in practice and demonstrated the ability to deliver an electrical power of 340 mW at a distance of 300 m, the HPL being configured at an optical emission power of 1.5 W, which represents a system efficiency of 22.6 %. PoF applications were extended to IoT and hazardous environment safety scenarios, including capabilities such as fiber optic fault detection, which is critical in explosive atmospheres. Additionally, a PoF platform was developed in which not only the power delivered to the load was increased to 1.95 W, but also the efficiency of the system was increased up to 36 %, positioning the solution among the best reported in the state of the art. On the other hand, this research has contributed to the development of the integration of PoF systems in communications, specifically with 5G technology, where the capability of the technology for the energy control of the RRH in a C-RAN scenario was demonstrated. The developed theoretical and experimental analysis allowed understanding the impact of nonlinear phenomena in the context of PoF technology, enabling the development of more efficient synergic systems, especially in the communications scenario. Long distance systems, over 10 km, based on SMF and MCF fibers were implemented. The system based on MCF fiber is the longest distance PoF solution explored with this type of fiber in the literature. Finally, a technique for monitoring the transmitted power in PoF systems was developed and patented.Programa de Doctorado en Ingeniería Eléctrica, Electrónica y Automática por la Universidad Carlos III de MadridPresidente: Ignacio Esquivias Moscardó.- Secretario: Sonia Martín López.- Vocal: Salvador E. Vargas Palm

Smart remote nodes fed by power over fiber in Internet of Things applications

Smart IoT solutions integrated into power grid stations are important due to their high economic and social value. Power over fiber technology to remotely feeding sensors and control electronics is a good choice in these environments of high electromagnetic interference. A sensing system design for magnetic field monitoring, fire and temperature/presence detection, and remotely fed by optical means is discussed. This design includes two types of nodes, smart and passive. Smart remote nodes have an energy manager to provide power on demand. Asymmetric splitting is proposed to optimize power distribution. Some tests on remote node power consumption, feeding, sensing, and centralized monitoring in one type of those nodes are successfully performed and reported.This work was supported in part by the Spanish Ministerio de Ciencia, Innovación y Universidades, Comunidad de Madrid and H2020 European Union Programme under Grants TEC2015-63826-C3-2-R and RTI2018-094669-B-C32, and Grant Y2018/EMT-4892 (TEFLON-CM), in part by FSE, and in part by 5G PPP Bluespace project under Grant nº 762055, respectively.Publicad

Power over Fiber in C-RAN with Low Power Sleep Mode Remote Nodes Using SMF

Power over fiber (PoF) with sleep mode operation in centralized radio access networks (C-RAN) of low power Remote Radio Heads (RRH) helps to reduce power consumption. This proposal includes bundles of single mode optical fibers (SMF) as part of the 5G C-RAN front-haul solution for providing control on power consumption by selectively activating some parts of the RRH. We experimentally demonstrate a PoF system based on 14.43 km of SMF feed by 2.24 W giving 226 mW electrical power at the RRH for control, battery charge, load operation and communication purposes. A bidirectional control channel is integrated in the central office and the RRH for providing the capability of entering in sleep mode operation and to provide information about the status of the battery and sensing elements at RRH. The optical data uplink/downlink operates over separate optical fibers shared by various RRHs and achieves low power consumption below 33 mW with low data rates. The measured PV cells conversion efficiency is above 30%. The RRH has two sleep modes of operation with a minimum power consumption of 5.8 mW.2021. This work was supported in part by the Spanish Ministerio de Ciencia, Innovación y Universidades, Madrid Government (Comunidad de Madrid-Spain) and H2020 European Union programme under Grants RTI2018-094669-B-C32, Y2018/EMT-4892, P2018/NMT-4326, and 5G PPP Bluespace Project Grant 762055, respectivel

Remote optical powering using fiber optics in hazardous environments

Potential niches for a 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 the 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.This work was supported in part by the Spanish Ministerio de Economía, Industria y Competitividad, Comunidad de Madrid and H2020 European Union Programme under Grants TEC2015-63826-C3-2-R and S2013/MIT-2790, in part by FSE, and in part by 5G PPP BlueSpace Project under Grant 762055.Publicad

Optically powered radio-over-fiber systems in support of 5G cellular networks and IoT

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.This work was supported in part by the Spanish Ministerio de Ciencia, Innovación y Universidades, Comunidad de Madrid and H2020 European Union programme under Grants RTI2018-094669-B-C32, Y2018/EMT-4892, and 5G PPP Bluespace project grant n°.762055, respectively

Optically feeding 1.75 W with 100 m MMF in efficient C-RAN front-hauls with Sleep Modes

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 mum 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.This work was supported in part by the Spanish Ministerio de Ciencia, Innovación y Universidades, Madrid Government (Comunidad de Madrid-Spain) and H2020 European Union programme under Grants RTI2018-094669-B-C32 and Y2018/EMT-4892, in part by Multiannual Agreement with UC3M in the line of Excellence of University Professors under Grant EPUC3M26, and in part by the context of the V PRICIT (Regional Programme of Research and Technological Innovation) and 5G PPP Bluespace project under Grant n°.762055, respectively.Publicad

Multicore fiber scenarios supporting power over fiber in radio over fiber systems

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.This work was supported in part by the Spanish Ministry of Science, Innovation and Universities, Directorate for Research and Innovation at Madrid region, and H2020 European Union programme under Grant RTI2018-094669-B-C32 and Grant Y2018/EMT-4892, and in part by FSE and 5G PPP Bluespace project Grant 762055

Fiber-Optic Pyrometer with Optically Powered Switch for Temperature Mesurements

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 degrees 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 degrees 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.This work was supported by the Spanish Ministry of Economy and Competitiveness and FEDER program under grants TEC2015-63826-C3-2-R and by Comunidad de Madrid under grant S2013/MIT-2790

Power-over-fiber in a 10 km long multicore fiber link within a 5G fronthaul scenario

We evaluate the impact of Power-over-Fiber (PoF) technology on the fronthaul of a 5G-NR network with an Analog-Radio-over-Fiber at 25.5 GHz on a 10 km long multicore fiber. The study in this Letter analyzes the bit error rate (BER) performance for different levels of energy transmitted by the PoF system. 133 mW of maximum optical power at reception is demonstrated showing negligible BER impact or data transmission BER improvement in a dedicated and shared scenario.Comunidad de Madrid (Y2018/EMT-4892); Ministerio de Ciencia, Innovación y Universidades (RTI2018-094669-B-C32); Horizon 2020 Framework Programme (762055)