K.A. Mekonnen

Ultra-High Capacity Indoor Optical Wireless Communication Using 2D-Steered Pencil Beams

Free-space indoor optical communication deploying pencil beams can offer ultra-high wireless capacity individually per user device. By means of two-dimensional (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. 2D angular beam steering over a 6° × 12° area was achieved by wavelength tuning from 1505 to 1630 nm. System experiments using PAM-4 modulation have shown a capacity of 32 Gbit/s per infrared beam. With radio-overfiber techniques and optical carrier recovery from the downstream signal, 10 Gbit/s upstream transmission of a 60 GHz radio signal has been shown using adaptive DMT modulation.

A Tunable Si3N4 Integrated True Time Delay Circuit for Optically-Controlled K-Band Radio Beamformer in Satellite Communication

In this paper we present the design, realization, and experimental characterization of a photonic integrated true time delay circuit on a CMOS-compatible Si3N4 platform. The true time delay circuit consists of an optical side band filter for single side band modulation and an optical ring resonator for broadband time delay. Two methods of optical delay tuning are investigated: 1) optical wavelength and 2) thermo-optic delay tuning. The wavelength controlled tuning enables a large delay tuning range and can be done remotely from a distant location. The close to a linear phase measurements can be used for full beam-scanning of radio signals with frequencies in the 20 GHz band. The thermal control results in a 5 GHz RF delay bandwidth. A proof-of-concept 2 × 1 beamforming is demonstrated in the 20 GHz band. The design presented here can be employed to realize multi-beams for multi-users serviced by multiple satellites.

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.

A photonics-assisted beamformer for K-band RF antenna arrays

We present an experimental demonstration of radio beamforming using an optical chip for application in K-band satellite communication. Via coherent combination of four RF channels, close to 12 dB beamforming gain is obtained. As a result, the transmission capacity is enhanced from 8-QAM, 5.81 Gbps to 32-QAM, 9.68 Gbps of multi-carrier data. For 4 channel beamforming, error-free performance (BER<1E-12) is obtained with 8-QAM data. The tuning of the optical beamforming chip is done electronically via a software interface by a computer.

2D beam-steered high-capacity optical wireless communication

The design of an indoor optical wireless communication network deploying high-capacity infrared optical beams with two-dimensional beam steering by means of wavelength tuning is discussed. Passive diffractive elements are used, yielding an easily scalable system as multiple beams can be steered independently by using multiple wavelengths.

High-Capacity Symmetric Dynamic Indoor Optical Wireless Communication Equipped With User Localization

We report on a novel all-optical system for ultra-high-capacity indoor wireless communication with centralized light sources. Using optical cross-connect and reflective modulator photonic chips, bidirectional dynamic indoor wireless networks equipped with localization and tracking functionalities are realized. This novel system allows us to harvest the ultimate bandwidth of optical communication in the wireless domain in a more cost-/energy-efficient manner. Bidirectional transmission capacities in excess of 40 Gb/s per user are demonstrated experimentally.

High-capacity dynamic indoor network utilizing optical wireless and 60-GHz radio techniques

We propose a full-duplex dynamic indoor optical-wireless system using photonic integrated circuits with multicasting capability of 10 Gb/s on-off-keying data, backed up by a 60-GHz radio fallback system, with data capacity of >40 Gb/s to realize reconfigurable and reliable high-capacity links to wireless users equipped with localization and tracking functionalities.

Indoor ultra-high capacity optical wireless communication using steerable infrared beams

Free-space infrared beams can offer unprecedented data capacity to devices individually, by means of unshared connections which have a large link power budget. Two solutions based on passive diffractive modules are presented which perform wavelength-controlled 2D beam steering while minimizing power consumption. Downstream capacities up to 112Gbit/s per beam were experimentally demonstrated. In a hybrid system demonstrator, 60GHz techniques provided upstream capacity up to 5Gbit/s. Also an all-optical optical wireless communication system concept has been demonstrated, and a novel concept for an aperture-and-bandwidth-optimized integrated optical receiver is presented.

Low-Crosstalk Full-Duplex All-Optical Indoor Wireless Transmission With Carrier Recovery

We propose and demonstrate a novel bi-directional free-space (FS) optical wireless communication system for indoor wireless networks. A 2-D infrared beam-steered system supporting full-duplex communication of at least 10 Gb/s capacity per wireless terminal with simple NRZ-OOK modulation format is experimentally demonstrated. The uplink (UL) is implemented using the optical carrier recovery technique, in which the downlink (DL) OOK modulation is erased by means of two cascaded SOAs operating in the saturation region. We experimentally demonstrate the system with asymmetric speeds (10 Gb/s DL/2.5 Gb/s UL) and symmetric speeds (10 Gb/s) duplex communication over an FS transmission distance of 3 m. We also report the crosstalk in such a system.

10 Gbps indoor optical wireless communication employing 2D passive beam steering based on arrayed waveguide gratings

We report an indoor optical wireless communication system based on 2D optical beam steering at using arrayed waveguide gratings. A data rate of 10Gbps is demonstrated with NRZ-OOK modulation maintaining BER ≤ 10-9, while keeping the optical transmitted power below the eye safety limit.