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Proceedings Paper

A novel free-space retrocommunication link
Author(s): Lars J. Sjoqvist; Emil J. Hallstig; Johan Ohgren; Lars Allard; Daniel Agren; Stephane Junique; Qin Wang; Bertrand Noharet; David Engstrom; Sverker Hard
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Paper Abstract

Retrocommunication is a new technique for asymmetric free-space optical communication that has attracted interest during recent years. Novel technologies such as multiple quantum well (MQW) optical modulators and non-mechanical laser beam steering and tracking have been studied for implementation in a retrocommunication link. Large and small aperture reflective AlGaAs/GaAs MQW modulators were optimised and fabricated. The modulators exhibit high contrast ratios (from 5 to 100) and high modulation rates (up to 16 Mbit/s). A retroreceiver consisting of four large aperture MQW modulators, associated optics and drive electronics was fabricated. Nematic liquid crystal spatial light modulators have been evaluated, characterised for beam steering and tracking and implemented in a transceiver. Small area MQW modulators, used in focal plane configurations, were studied for static communication links. Results from a novel retrocommunication link utilising a retroreceiver and non-mechanical laser beam steering and tracking will be presented. Bit rates of 8 Mbit/s were observed during non-mechanical tracking of a moving retroreceiver over 100 m range. The demonstrator system was capable of transferring audio-, real-time images or bit streams. The demonstrated principles show promising features for future low weight free-space communication links. Performance calculations including requirements for a retrocommunication link using MQW modulators and non-mechanical beam steering are discussed.

Paper Details

Date Published: 8 December 2004
PDF: 14 pages
Proc. SPIE 5614, Advanced Free-Space Optical Communications Techniques and Technologies, (8 December 2004);
Show Author Affiliations
Lars J. Sjoqvist, Swedish Defence Research Agency (Sweden)
Emil J. Hallstig, Swedish Defence Research Agency (Sweden)
Johan Ohgren, Swedish Defence Research Agency (Sweden)
Lars Allard, Swedish Defence Research Agency (Sweden)
Daniel Agren, Acreo AB (Sweden)
Stephane Junique, Acreo AB (Sweden)
Qin Wang, Acreo AB (Sweden)
Bertrand Noharet, Acreo AB (Sweden)
David Engstrom, Chalmers Univ. of Technology (Sweden)
Sverker Hard, Chalmers Univ. of Technology (Sweden)

Published in SPIE Proceedings Vol. 5614:
Advanced Free-Space Optical Communications Techniques and Technologies
Monte Ross; Andrew M. Scott, Editor(s)

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