1,883 research outputs found
A Comparative Survey of Optical Wireless Technologies: Architectures and Applications
New high-data-rate multimedia services and applications are evolving
continuously and exponentially increasing the demand for wireless capacity of
fifth-generation (5G) and beyond. The existing radio frequency (RF)
communication spectrum is insufficient to meet the demands of future
high-datarate 5G services. Optical wireless communication (OWC), which uses an
ultra-wide range of unregulated spectrum, has emerged as a promising solution
to overcome the RF spectrum crisis. It has attracted growing research interest
worldwide in the last decade for indoor and outdoor applications. OWC offloads
huge data traffic applications from RF networks. A 100 Gb/s data rate has
already been demonstrated through OWC. It offers services indoors as well as
outdoors, and communication distances range from several nm to more than 10000
km. This paper provides a technology overview and a review on optical wireless
technologies, such as visible light communication, light fidelity, optical
camera communication, free space optical communication, and light detection and
ranging. We survey the key technologies for understanding OWC and present
state-of-the-art criteria in aspects, such as classification, spectrum use,
architecture, and applications. The key contribution of this paper is to
clarify the differences among different promising optical wireless technologies
and between these technologies and their corresponding similar existing RF
technologie
A study of weather-dependent data links for deep space applications
Weather-dependent data links for deep space applications, and five potential system
Invisibility Cloak Printed on a Photonic Chip
Invisibility cloak capable of hiding an object can be achieved by properly
manipulating electromagnetic field. Such a remarkable ability has been shown in
transformation and ray optics. Alternatively, it may be realistic to create a
spatial cloak by means of confining electromagnetic field in three-dimensional
arrayed waveguides and introducing appropriate collective curvature surrounding
an object. We realize the artificial structure in borosilicate by femtosecond
laser direct writing, where we prototype up to 5000 waveguides to conceal
millimeter-scale volume. We characterize the performance of the cloak by
normalized cross correlation, tomography analysis and continuous
three-dimensional viewing angle scan. Our results show invisibility cloak can
be achieved in waveguide optics. Furthermore, directly printed invisibility
cloak on a photonic chip may enable controllable study and novel applications
in classical and quantum integrated photonics, such as invisualising a coupling
or swapping operation with on-chip circuits of their own.Comment: 9 pages, 6 figure
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