Ultrahigh-capacity optical-wireless communication using 2D gratings for steering and decoding of DPSK signals

We demonstrate the use of a 2D-gratings beam-steering device also as a demodulator for multiple differentially-encoded optical-wireless signals. Using this novel concept, ~2bits/sec/Hz spectral-efficiency was achieved without any change in the system compared to on-off-keying

Compact OWC Receiver:Micro-Lens and PD Array on Glass Interposer

In this article, we propose a compact optical wireless receiver based on micro-lens and photodiode array flip-chipped on a glass interposer. With simulation models and experiments, we verify the performance of two optical wireless communication receivers assembled based on this structure with gigabit and high-speed photodiodes. First, co-integrated gigabit photodiodes and micro-lenses indicate that micro-lenses can deliver a 3.5 dB gain of light collection efficiency to the gigabit photodiode array while keeping the field of view larger than ±18 degrees. Besides, a 5.5 Gbps maximum throughput has been verified by this optical wireless communication receiver with discrete multitone modulation. Moreover, co-integrated high-speed photodiodes and micro-lenses prove that micro-lenses realize a 26.6 dB improvement in light collection efficiency, enabling a 10 Gbps error-free connection using as little as-0.5 dBm transmission power. Those results conclude that the co-integration of micro-lenses on the photodiode array can enhance the light collection efficiency of the photodiode array while keeping a larger field of view, providing a high-performance, low-cost solution for the receiver of optical wireless links.</p

Bi-directional All-Optical Wireless Communication System with Optical Beam steering and Automatic Self-Alignment

A Gigabit Ethernet bidirectional OWC system with user-hosted automatic alignment of the upstream beams is demonstrated, using miniature retroreflectors and novel self-alignment algorithm. It provides individual narrow beams for high user densities. TCP measurements show transfer speeds of 940Mbit/s per user within 10 degrees Field-of-View.</p

Bi-Directional All-Optical Wireless Gigabit Ethernet Communication System Using Automatic Self-Aligned Beam Steering

A beam-steered Gigabit Ethernet (GbE) bidirectional OWC system with user-hosted automatic self-calibrated alignment of the upstream beams has been designed and realized, using stepper motor translators, miniature retro-reflectors and a novel self-alignment center-of-gravity (CoG) algorithm. Broadband receivers with a Field-of View (FoV) &gt;10 degree are used, which relaxes beam alignment. The accuracy of the CoG algorithm and the impact of lens aberrations in the upstream beam launching is analyzed. A good accuracy of the automated upstream beam steering within 200 μm relative to the center of the upstream receiver's aperture has been found up to a beam incident angle of 10 degree; this is well within the 25 mm aperture and the FoV of the upstream receiver. Hereto a relatively simple low-aberration triplet lens is used at the user site. The upstream beam alignment takes less than 10 seconds. The full system laboratory setup provides individual narrow beams for high user densities. It also includes automatic self-calibrated alignment of the downstream beams using similar retroreflector technology and a wavelength-tuned beam steering. TCP measurements show transfer speeds of 940 Mbit/s per user within 10 degree FoV. Real-time high-definition GbE video streaming to laptop computers via individual bidirectional OWC links has been demonstrated.</p

High-capacity dynamic indoor all-optical-wireless communication system backed-up with millimeter-wave radio techniques

We propose a full-duplex dynamic indoor optical-wireless communication system using a crossed pair of diffraction gratings and photonic-integrated circuits with multicasting capability of 10-Gb/s on-off-keying and >40-Gb/s discrete-multitone data per user, backed up by a 60-GHz radio fallback system, with shared capacity of ∼40 Gb/s to realize reconfigurable and reliable high-capacity links to wireless users equipped with localization and tracking functionalities. The use of semiconductor optical amplifiers integrated with reflective electroabsorption modulators allows us to provide cost-efficient reflective transmitters at the user terminals in the upstream using centralized light sources and wavelength reuse technique. The 60-GHz radio fallback system allows us to cope with line-of-sight blocking in the optical-wireless links, thereby significantly enhancing the reliability of the wireless communication system

Ultra-high capacity indoor optical wireless communication using steered pencil beams

Free-space indoor optical communication deploying pencil beams can offer ultra-high wireless capacity individually per user device. By means of 2D diffractive modules, such as a pair of crossed gratings, 2D steering of multiple beams by just tuning the wavelength of each beam can be achieved. The design aspects of an indoor system fed via an intelligent optical fiber backbone network are discussed. First experiments have shown a capacity of 42.8Gbit/s per infrared beam