Free space laser communications

Free Space LASER Communication
Abstract – In space, radio frequencies (RFs) are usually used for long-distance linkage. However, recent progress in optics and laser technologies,especially in fiber optics, is ushering in an era of inter-orbit communications using laser beams.Communication technology has experienced a continual development to higher and higher carrier Frequencies, starting from a few hundred kilohertz at Marconi’s time to several hundred terahertz since we employ lasers in fiber systems. The main driving force was that the usable bandwidth and hence Transmission capacity increases proportional to the carrier frequency. Another asset comes into play in free-space point-to-point links. The benefits are due to optical waves’ high frequency. In Europe, the European Space Agency (ESA)in its Semiconductor Laser Inter satellite Link Experiment (SILEX) has routinely used a 50Mbps optical communication link twice a day between a low earth orbit (LEO) and geostationary earth orbit (GEO) satellite since 2003. In Japan, the Optical Inter-orbit Communications Engineering Test Satellite (OICETS) developed by the Japan Aerospace Exploration Agency (JAXA) was launched in August 2005 and a laser communication link with the SILEX terminal was successfully established.
INTRODUCTION
The Optical Inter-orbit Communications Engineering Test Satellite (OICETS), developed by the Japan Aerospace Exploration Agency (JAXA), was launched in August 2005, which led to the world’s first successful bidirectional intersatellite laser communications experiment, between the OICETS and the Advanced Relay Technology Mission Satellite (ARTEMIS), a geostationary earth orbit (GEO) satellite of the European Space Agency (ESA). Laser Communication is one.