Latest Papers Related to OWPT 2023 on the Topics of Devices, Components and Systems

A special issue of Photonics (ISSN 2304-6732). This special issue belongs to the section "New Applications Enabled by Photonics Technologies and Systems".

Deadline for manuscript submissions: closed (31 January 2024) | Viewed by 15165

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Guest Editor
Photonics Research Laboratory, University of Electro-Communications, Tokyo 182-8585, Japan
Interests: power over fiber; optical communication
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Special Issue Information

Dear Colleagues,

Electrical power transmission is an essential function of equipment. Although wiring, batteries, and energy harvesting have been used, these methods have various problems. By solving the problem of power transmission, society can be further developed with new equipment and new services. Power transmission methods using light beams are attracting attention as promising technologies. The first is power transmission in wireless, just as wireless communication has greatly progressed society. Optical wireless power transmission (OWPT) is extremely promising because of its potential for long-distance power transmission, no electromagnetic interference, and small size and lightweight. The second is power transmission using an optical fiber. Power over fiber (PoF) has the superior potential to provide new value to the next infrastructure by taking advantage of features not provided in existing wiring, such as surge resistance, integration with extremely high-capacity communications, and lightweight.

These optical power transmission technologies will be applied in the near future to a wide variety of applications from minute IoT terminals to home appliances, industrial equipment, mobilities such as electric vehicles, robots, and drones, and power transmission infrastructure in various environments where conventional methods are difficult to apply. On the other hand, although the basic technical functions of these optical power transmission technologies already exist, practical and commercial systems are still very limited, and thus, the activation of related research is strongly demanded the development of many applications. By clarifying the superiority of this optical power transmission and the problems to be solved and collecting the state-of-the-art features of this field, such as materials, devices, subsystems, systems, and applications, as well as safety and standardization, it will be possible to bring many social values in the near future.

For this reason, we have decided to publish a Special Issue that contains the latest results. Although this field is related to energy and photonics technologies, it is configured by a wide range of technologies such as materials, devices, systems, and applications as described above. This Special Issue will target papers that are related widely to individual devices like light sources and light-receiving devices, functional integration, systems, and applications of optical power transmission.

Dr. Tomoyuki Miyamoto
Prof. Dr. Motoharu Matsuura
Guest Editors

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Keywords

  • optical wireless power transmission
  • laser power beaming
  • power over fiber
  • OWPT subsystem
  • OWPT system

Related Special Issue

Published Papers (10 papers)

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Research

12 pages, 4410 KiB  
Communication
Optimal Photovoltaic Array Configuration under Non-Uniform Laser Beam Conditions for Laser Wireless Power Transmission
by Zhiqiang Mou, Bangbo Zhao, Lihong Zhu, Jun Wang, Guoliang Deng, Huomu Yang and Yudan Gou
Photonics 2024, 11(3), 193; https://doi.org/10.3390/photonics11030193 - 21 Feb 2024
Viewed by 972
Abstract
In a long-distance wireless power transmission system with a non-uniform distribution of laser irradiation, it will significantly reduce the output power of the photovoltaic array, resulting in a large amount of power loss in the system and a decrease in conversion efficiency. This [...] Read more.
In a long-distance wireless power transmission system with a non-uniform distribution of laser irradiation, it will significantly reduce the output power of the photovoltaic array, resulting in a large amount of power loss in the system and a decrease in conversion efficiency. This paper proposes an efficient and reliable optimal circuit connection algorithm for the 5 × 5 scale photovoltaic array. Under the laser illumination of 300 W, a 20 m wireless power transmission experiment was performed on four 5 × 5 scale photovoltaic arrays. The results show a 56.49% increase in the maximum output power of the 5 × 5 scale photovoltaic array. Full article
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11 pages, 2109 KiB  
Article
67.5% Efficient InP-Based Laser Power Converters at 1470 nm at 77 K
by Simon Fafard and Denis Masson
Photonics 2024, 11(2), 130; https://doi.org/10.3390/photonics11020130 - 30 Jan 2024
Cited by 1 | Viewed by 1357
Abstract
Recent developments in long wavelength and cryogenic laser power converters have unlocked record performances in both areas. Here, devices for an optical input at ~1470 nm are studied for cryogenic applications, combining these cryogenic and long-wavelength attributes. Multijunction laser power converters are demonstrated [...] Read more.
Recent developments in long wavelength and cryogenic laser power converters have unlocked record performances in both areas. Here, devices for an optical input at ~1470 nm are studied for cryogenic applications, combining these cryogenic and long-wavelength attributes. Multijunction laser power converters are demonstrated to have a high-efficiency operation at 77 K. The photovoltaic-power-converting III-V semiconductor devices are designed with InGaAs-absorbing layers, here with 10 thin subcells (PT10), connected by transparent tunnel junctions. Unprecedented conversion efficiencies of up to 67.5% are measured at liquid nitrogen temperatures with an output power of Pmpp = 1.35 W at an average optical input intensity of ~62 W/cm2. A remarkably low bandgap voltage offset value of Woc~50 mV is obtained at an average optical input intensity of ~31 W/cm2. Full article
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15 pages, 5385 KiB  
Article
Experimentation and Analysis of Intra-Cavity Beam-Splitting Method to Enhance the Uniformity of Light in the Powersphere
by Tiefeng He, Guobing Pan, Guoliang Zheng, Zikun Xu, Zhijian Lv, Qingyang Wu, Lili Wan, Haixuan Huang and Tianyu Shi
Photonics 2024, 11(2), 128; https://doi.org/10.3390/photonics11020128 - 29 Jan 2024
Viewed by 840
Abstract
The powersphere is a spherical enclosed receiver composed of multiple photovoltaic cells. It serves as a replacement for traditional photovoltaic panels in laser wireless power transmission systems for optoelectronic conversion. The ideal powersphere aims to achieve a uniform distribution of light within the [...] Read more.
The powersphere is a spherical enclosed receiver composed of multiple photovoltaic cells. It serves as a replacement for traditional photovoltaic panels in laser wireless power transmission systems for optoelectronic conversion. The ideal powersphere aims to achieve a uniform distribution of light within the cavity through infinite reflections, reducing energy losses in the circuit. However, due to the high absorption rate of the photovoltaic cells, the direct irradiation area on the inner surface of the powersphere exhibits a significantly higher light intensity than the reflected area, resulting in a suboptimal level of light uniformity and certain circuit losses. To address the aforementioned issues, a method of intra-cavity beam splitting in the powersphere is proposed. This solution aims to increase the area of direct illumination and reduce the intensity difference between direct and reflected lights, thereby improving the light uniformity on the inner surface of the powersphere. Utilizing the transformation matrix of Gaussian beams, the q parameters for each optical path with beam splitting were calculated, and the equality of corresponding q values was demonstrated. Further, based on the q parameter expression for the electric field of Gaussian beams, the intensities for each optical path were calculated, and it was demonstrated that their values are equal. Additionally, an optical software was utilized to establish a model for intra-cavity beam splitting in the powersphere. Based on this model, a beam-splitting system was designed using a semi-transparent and semi-reflective lens as the core component. The light uniformity performance of the proposed system was analyzed through simulations. To further validate the effectiveness of the calculations, design, and simulations, multiple lenses were employed to construct the beam-splitting system. An experimental platform was set up, consisting of a semiconductor laser, monocrystalline silicon photovoltaic cells, beam expander, Fresnel lens, beam-splitting system, and powersphere. An experimental verification was conducted, and the results aligned with the theoretical calculations and simulated outcomes. The above theory, simulations, and experiments demonstrate that the intra-cavity beam-splitting method effectively enhances the optical uniformity within the powersphere. Full article
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12 pages, 1903 KiB  
Communication
Onset of Quantum-Confined Stark Effects in Multijunction Photovoltaic Laser Power Converters Designed with Thin Subcells
by Simon Fafard and Denis Masson
Photonics 2023, 10(11), 1243; https://doi.org/10.3390/photonics10111243 - 8 Nov 2023
Cited by 2 | Viewed by 1403
Abstract
Photovoltaic multijunction power-converting III–V semiconductor devices generate electrical power from the optical energy of laser beams. They exhibit conversion efficiencies reaching values greater than 60% and 50% for the GaAs and the InP material systems, respectively. The applications of optical wireless power transmission [...] Read more.
Photovoltaic multijunction power-converting III–V semiconductor devices generate electrical power from the optical energy of laser beams. They exhibit conversion efficiencies reaching values greater than 60% and 50% for the GaAs and the InP material systems, respectively. The applications of optical wireless power transmission and power-over-fiber greatly benefit from employing such laser power converters constructed with multiple subcells; each is designed with either thin GaAs or InGaAs absorber regions. This study elucidates how the application of electric fields on thin heterostructures can create specific current–voltage characteristics due to modifications of the absorption characteristics from Franz–Keldysh perturbations and the onset of quantum-confined Stark effects. Negative differential photocurrent behavior can be observed as the reverse bias voltage is increased, until the corresponding current-clamping subcell reaches its reverse breakdown condition. The reverse voltage breakdown characteristics of the subcells were also measured to depend on the thickness of the subcell and on the optical intensity. The onset of the reverse breakdown was found to be at ~2.0–2.5 V under illumination and the thinner subcells exhibited higher levels of reverse bias currents. These effects can produce distinctive current–voltage behavior under spectrally detuned operations affecting the thinner subcells’ biases, but have no significant impact on the performance and maximum power point of multijunction power converters. Full article
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17 pages, 11338 KiB  
Article
Analysis and Experiment of Laser Energy Distribution of Laser Wireless Power Transmission Based on a Powersphere Receiver
by Tiefeng He, Guoliang Zheng, Qingyang Wu, Haixuan Huang, Lili Wan, Keyan Xu, Tianyu Shi and Zhijian Lv
Photonics 2023, 10(7), 844; https://doi.org/10.3390/photonics10070844 - 21 Jul 2023
Cited by 4 | Viewed by 1988
Abstract
Laser wireless power transmission (WPT) is one of the most important technologies in the field of long-range power transfer. This technique uses a laser as a transmission medium instead of conventional physical or electrical connections to perform WPT. It has the characteristics of [...] Read more.
Laser wireless power transmission (WPT) is one of the most important technologies in the field of long-range power transfer. This technique uses a laser as a transmission medium instead of conventional physical or electrical connections to perform WPT. It has the characteristics of long transmission distance and flexible operation. The existing laser wireless power transmission system uses photovoltaic cells as a receiver, which convert light into electricity. Due to the contradiction between the Gaussian distribution of laser and the uniform illumination requirements of photovoltaic cells, the laser wireless power transmission technology has problems such as low transmission efficiency and small output power. Therefore, understanding the energy distribution changes in the laser during transmission, especially the energy change after the laser is transmitted to each key device, and analyzing the influencing factors of the energy distribution state, are of great significance in improving the transmission efficiency and reducing the energy loss in the system. This article utilizes the optical software Lighttools as a tool to establish a laser wireless power transmission model based on a powersphere. This model is used to study the energy distribution changes in the laser as it passes through various components, and to analyze the corresponding influencing factors. To further validate the simulation results, an experimental platform was constructed using a semiconductor laser, beam expander, Fresnel lens, and powersphere as components. A beam quality analyzer was used to measure and analyze the laser energy distribution of each component except for the powersphere. The output voltage and current values of various regions of the powersphere were measured using a multimeter. The energy distribution of the powersphere was reflected based on the linear relationship between photo-generated current, voltage, and light intensity. The experimental results obtained were in good agreement with the simulation results. Simulations and experiments have shown that using a beam expander can reduce divergence angle and energy loss, while employing large-aperture focusing lens can enhance energy collection and output power, providing a basis for improving the efficiency of laser wireless power transfer. Full article
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12 pages, 6089 KiB  
Article
Efficient LED-Array Optical Wireless Power Transmission System for Portable Power Supply and Its Compact Modularization
by Mingzhi Zhao and Tomoyuki Miyamoto
Photonics 2023, 10(7), 824; https://doi.org/10.3390/photonics10070824 - 14 Jul 2023
Cited by 2 | Viewed by 1710
Abstract
Optical wireless power transmission (OWPT) has been a promising solution for remote power supply, eliminating the need for power cables or batteries. In this paper, we propose a light emitting diode (LED) array based OWPT system with improved transmission efficiency and compact system [...] Read more.
Optical wireless power transmission (OWPT) has been a promising solution for remote power supply, eliminating the need for power cables or batteries. In this paper, we propose a light emitting diode (LED) array based OWPT system with improved transmission efficiency and compact system dimension. In this experiment, the proposed four-LED-array collimation scheme achieved a lens system efficiency as high as 70%, while obtaining an electrical power of 0.8 W from a 50 × 50 mm2 GaAs solar cell at 1 m. The emitting side with the lens system was integrated into a 120 × 114 × 61 mm3 portable device by 3D printing. In addition, the thermal performance of the integrated module and the effective surface irradiance at the receiving side were analyzed in detail. The proposed system exhibits high efficiency and portability, with the advantageous potential to temporarily power remote devices. Full article
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23 pages, 11416 KiB  
Article
Solar Cell Detection and Position, Attitude Determination by Differential Absorption Imaging in Optical Wireless Power Transmission
by Kaoru Asaba and Tomoyuki Miyamoto
Photonics 2023, 10(5), 553; https://doi.org/10.3390/photonics10050553 - 10 May 2023
Cited by 5 | Viewed by 1180
Abstract
In optical wireless power transmission, position, size, and attitude of photovoltaic device (PV) must be determined from light source. A method proposed in the previous report is based on selective absorption characteristics of PV, and it is detected by differentiating images of strongly [...] Read more.
In optical wireless power transmission, position, size, and attitude of photovoltaic device (PV) must be determined from light source. A method proposed in the previous report is based on selective absorption characteristics of PV, and it is detected by differentiating images of strongly absorbable wavelength and one not. In this study, using two infrared wavelengths, two kinds of targets were detected by differential absorption imaging. One was a GaAs substrate which simulates diffuse rear surface, and the other was a real GaAs PV. It was found that the substrate’s reflective characteristic was diffuse, and the solar cell’s was mainly non-diffuse and accompanied by small diffuse component supporting wide-angle reflection. Using this feature, the position of the GaAs solar cell could be determined within a wide range of angle. Its attitude could also be determined with an accuracy of ±10 degrees to its normal. The position of diffuse GaAs substrate could be determined within a wide range of angles, and its attitude determination was proposed by exploiting its varying apparent size with tilt angle. Broad reflection characteristics of the GaAs substrate enabled attitude determination for a wide-angle range, and determination around normal would be erroneous. Full article
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10 pages, 3010 KiB  
Article
Multi-Channel Long-Distance Audio Transmission System Using Power-over-Fiber Technology
by Can Guo, Chenggang Guan, Hui Lv, Shiyi Chai and Hao Chen
Photonics 2023, 10(5), 521; https://doi.org/10.3390/photonics10050521 - 1 May 2023
Cited by 4 | Viewed by 1982
Abstract
To establish stable communication networks in harsh environments where power supply is difficult, such as coal mines and underwater, we propose an effective scheme for co-transmission of analog audio signals and energy. By leveraging the advantages of optical fibers, such as corrosion resistance [...] Read more.
To establish stable communication networks in harsh environments where power supply is difficult, such as coal mines and underwater, we propose an effective scheme for co-transmission of analog audio signals and energy. By leveraging the advantages of optical fibers, such as corrosion resistance and strong resistance to electromagnetic interference, the scheme uses a 1550 nm laser beam as the carrier for analog audio signal propagation, which is then converted to electrical energy through a custom InGaAs/InP photovoltaic power converter (PPC) for energy supply and information transfer without an external power supply after a 25 km fiber transmission. In the experiment, with 160 mW of optical power injection, the scheme not only provides 4 mW of electrical power, but also transmits an analog signal with an acoustic overload point (AOP) of 105 dBSPL and a signal-to-noise ratio (SNR) of 50 dB. In addition, the system employs wavelength division multiplexing (WDM) technology to transform from single-channel to multi-channel communication on a single independent fiber, enabling the arraying of receiving terminals. The passive arrayed terminals make the multi-channel long-distance audio transmission system using power-over-fiber (PoF) technology a superior choice for establishing a stable communication network in harsh environments. Full article
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16 pages, 2512 KiB  
Article
Downtaper on Multimode Fibers towards Sustainable Power over Fiber Systems
by Alicia Fresno-Hernández, Marta Rodríguez-Guerra, Roberto Rodríguez-Garrido and Carmen Vázquez
Photonics 2023, 10(5), 513; https://doi.org/10.3390/photonics10050513 - 28 Apr 2023
Viewed by 1422
Abstract
This paper presents a transition taper for coupling light between optical fibers with different geometries and refractive index profiles used in Power over Fiber (PoF) systems. Global energy efficiency and costs are critical parameters when delivering high power to remote areas. High-power lasers [...] Read more.
This paper presents a transition taper for coupling light between optical fibers with different geometries and refractive index profiles used in Power over Fiber (PoF) systems. Global energy efficiency and costs are critical parameters when delivering high power to remote areas. High-power lasers have maximum coupling for large core fibers, while widespread multimode optical (OM1) fibers used in optical communications are cheaper. We study the optical losses between large core fibers (200 µm) and OM1 fibers (62.5 µm) theoretically and experimentally. We demonstrate that improvements of 2 dB can be obtained by adding the new tapered structure to the system, compared to the direct splice between both fibers. There is good agreement between measured and calculated loss values using a new Gaussian loss model to describe splices between tapered and straight fibers. The fabrication of the transition taper is also described. We also measure the numerical aperture (NA) changes in the downtaper zone and demonstrate that the lower the NA of the input light, the higher the efficiency improvement. Full article
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12 pages, 3521 KiB  
Communication
Cylindrical Waveguides and Multi-Junction Solar Cell Investigated for Two-Dimensional Photorecepto-Conversion Scheme
by Yubo Wang, Xingbai Hong, Dan Wu, He Wu and Akira Ishibashi
Photonics 2023, 10(3), 299; https://doi.org/10.3390/photonics10030299 - 12 Mar 2023
Viewed by 1195
Abstract
Presented is a new cylindrical waveguide (WG) system based on a two-dimensional photoreceptor-conversion scheme (2DPRCS) for lamppost-type solar-cell systems. The optical properties of polydimethylsiloxane (PDMS) were evaluated as the WG material, and we found that the intrinsic optical loss of our PDMS-based waveguide [...] Read more.
Presented is a new cylindrical waveguide (WG) system based on a two-dimensional photoreceptor-conversion scheme (2DPRCS) for lamppost-type solar-cell systems. The optical properties of polydimethylsiloxane (PDMS) were evaluated as the WG material, and we found that the intrinsic optical loss of our PDMS-based waveguide (~3 m−1) is low enough to be used in a 50 mm diameter lamppost 2DPRCS. The reflection solar concentrator (RSC) is also proposed, which can be combined with multijunction Si solar cells for lamppost-type systems that utilize sunlight coming not only from the south side but also from the east and west sides. We believe that, in the near future, this new approach based on 2DPRCS can enable high-efficiency concentrated photovoltaic systems. Full article
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