KEYWORDS: Acquisition tracking and pointing, Beam steering, Receivers, Beam divergence, Signal detection, Transmitters, Retroreflectors, Analog to digital converters, Reflection, Mirrors, Diffraction gratings
A significant challenge faced by Wireless Optical Power Transfer (WOPT) using the Resonant Beam Charging (RBC) method is the restrictive alignment requirement. In this study, we examine the utilization of a diverging angular dispersion beam and active beam steering to enhance the likelihood of identifying and maintaining a resonant link. The system exhibits significant improvements compared to conventional systems that utilize pencil beams. This enhancement is observed during the initial search for the receiver position, and it contributes to maintaining resonance cavity between the two beam types. These findings highlight the potential of utilizing diverging angular dispersion beams for real-time charging applications in future research.
This study explores the efficacy of Wireless Optical Power Transfer (WOPT) for secure long-range wireless power transmission, particularly at extended wavelengths. A novel approach, infrared wireless charging, leverages retroreflectors for simplified alignment. The presented WOPT system incorporates an Erbium-Doped Fiber Amplifier (EDFA) operating at 1550 nm. The reflectivity and transmissivity of a spherical ball lens retroreflector are summarized and compared to optimize power transfer. Achieving resonant cavities between the transmitter and receiver requires precise beam alignment, yielding 750 mW at 1 meter and 500 mW over 30 meters at an Amplified Spontaneous Emission (ASE) output power of 1 W. A power loss budget analysis highlights challenges in power transmission, mitigated by adjusting the beam spot size. Examination of incidence angles reveals limitations, with optimal performance up to a 60° angle. These findings emphasize the safety, efficiency, and limitations of the proposed RBC system, offering insights for advancing long-range Wireless Optical Power Transfer (WOPT) systems.
This study provides a novel two-dimensional beam steering mechanism that takes advantage of wireless optical power systems utilizing diverging angular dispersion laser beams and the resonant beam charging technique. The system exhibits significant improvements compared to conventional systems that utilize pencil beams. These enhancements include reducing scanning time, capable of mitigating inherent errors, and increasing the ability to charge resonant cavities continuously. Specifically, our system exhibits scanning times that are 1.2 times faster than traditional systems. This opens the pathway for practical deployments of beam steering for RBC-based WOPT, enabling real-time charging and communication.
Resonant beam charging (RBC) is a promising alternative to traditional wireless power technologies (WPT) considering the safety and long-range power transmission parameters. RBC has an excellent feature of self-alignment of an optical beam to make a strong connection between transmitter and receiver using retroreflectors. However, there are certain limitations in selecting an appropriate retroreflector considering the receiver size, Photovoltaic (PV) cell efficiency, and wide field of view for mobile receiver charging. The current investigation showcases a promising configuration of a practical receiver for optical wireless charging applications. The receiver incorporates a small 2 mm ball lens retroreflector with refractive index 1.967 at 1060 nm to establish a resonant cavity. The ball lens has highly reflection (HR) coating on the rear side to achieve a sufficient reflective signal and an anti-reflection (AR) coating on the front side to avoid surface reflections. This coated small ball lens features a wide field of view (FOV) upon using a large beam diameter, making it ideal to be used in optical receiver for mobile receiver charging. The performance of proposed receiver is evaluated using a semiconductor optical amplifier (SOA) as a gain medium operating in a bidirectional scheme at a center wavelength of 1060 nm. The proposed receiver model can potentially enhance the illumination area on the photovoltaic receiver, thereby increasing its efficiency. To validate the performance of the proposed model, a GaSb PV cell is used in the scheme, which ensures a peak efficiency of 25%.
Utilizing Wireless Optical Power Transfer (WOPT) at extended wavelengths offers a secure means of long-range wireless power transmission. An innovative approach known as Resonance Beam Charging (RBC) has been recently introduced, employing retroreflectors for simplified alignment. This investigation presents a WOPT system incorporating an Erbium-Doped Fiber Amplifier (EDFA) that functions at 1550 nm. We have summarized and compared the reflectivity and transmissivity of a spherical ball lens retroreflector when interacting with the incident beam to optimize power transfer. The system yields an electrical power output of 0.5 Watts, covering a span of 25 meters. The experiment scrutinizes a gallium antimonide photovoltaic cell, achieving a notable 23 percent conversion efficiency from optical to DC-electrical energy. In the final phase, a mathematical assessment is conducted to determine the safe power levels for human skin and eyes, adhering to the Laser safety standards' Maximum Permissible Exposure (MPE) thresholds. The receiver model can potentially enhance the illumination area on the photovoltaic receiver, thereby increasing its efficiency. To validate the performance of the proposed model, a GaSb PV cell is used in the scheme.
The input power dynamic range (IPDR) of a semiconductor optical amplifier (SOA) is extended using a moderate power holding beam, which could be readily achieved with a single DFB laser. The associated reduction of gain with improved IPDR is studied and assessed in parallel with power penalty to explore the optimum operating powers in switching applications. Holding beam powers of less than +10 dBm facilitate IPDR enhancement to 27 dB, representing an order of magnitude improvement. The achievable gain remains sufficiently high to find applications in a number of switching and routing applications.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.