The satellite market is shifting towards smaller (micro and nanosatellites), lowered mass and increased performance platforms. Nanosatellites and picosatellites have been used for a number of new, innovative and unique payloads and missions. This trend requires new concepts for a reduced size, a better performance/weight ratio and a reduction of onboard power consumption. In this context, disruptive technologies, such as laser-optical communication systems, are opening new possibilities. This paper presents the C3PO<sup>1</sup> system, “advanced Concept for laser uplink/ downlink CommuniCation with sPace Objects”, and the first results of the development of its key technologies. This project targets the design of a communications system that uses a ground-based laser to illuminate a satellite, and a Modulating Retro-Reflector (MRR) to return a beam of light modulated by data to the ground. This enables a downlink, without a laser source on the satellite. This architecture suits well to small satellite applications so as high data rates are potentially provided with very low board mass. C3PO project aims to achieve data rates of 1Gbit/s between LEO satellites and Earth with a communication payload mass of less than 1kilogram. In this paper, results of the initial experiments and demonstration of the key technologies will be shown.
Fibre-to-the-home deployment is enabling ultra-high speed communications to reach the end-user in many cities. Most users would like to access this capacity using wireless devices. However, available wireless technologies can handle data rates often many orders of magnitude slower than those potentially offered by the fibre infrastructure. This paper describes an optical wireless architecture that bridges this gap by using the light directly from the fibre to create an indoor point-to-multipoint transparent distribution system. The approach is all optical, thus inherently independent of the data-rate and modulation formats. A holographic beamsteering device is used to direct narrow 1550 nm beams to the receivers' locations. Specifically, a spatial light modulator (SLM), assisted by angle magnification optics allowed for a ±30° field-of-view coverage in both the horizontal and vertical directions. In this work we experimentally study two different methods to generate the point-to-multipoint capability: spatial division of the SLM in independent phaseprogrammable regions and the Gerchberg-Saxton (GS) multipoint hologram generation algorithm. These methods were compared for a 2-beam beamsteering system at a range of ~ 2 meters. Results show that the spatial division approach creates more stable links with higher optical margins. However, the GS-based steering offers a more scalable solution for a point-to-multipoint architecture that addresses a large number of end-users.
The new generation of UAVs (Unmanned Aerial Vehicles) require high speed data links to offload all its sensors data.
RFSO (Reflective Free Space Optics) has become an important alternative to RF systems because it is robust against
interception and jamming, enhancing data security. Moreover, the weight and power consumption of the RFSO coms
module is reduced, making it suitable for SWaP (Size, Weight, and Power) constrained applications.
In this paper, we present the design of a tracking module based on a non-mechanical holographic beam steering system.
A highly accurate position sensing unit is required to accomplish a good tracking process and therefore guarantee the
data link stability. Different localization methods such as centroid, centroid windowed or centroid squared are tested and
compared using real data captured in a turbulent scenario. Errors below 8cm are reported in a double pass 1km link.