17-09-2014, 03:30 PM
Lasers have been considered for space communications since their realization in 1960. However, it was soon recognized that, although the Laser had potential for the transfer of data at extremely high rates, specific advancements were needed in component performance and systems engineering, particularly for space-qualified hardware.Advances in system architecture, data formatting, and component technology over the past three decades have made Laser communication pace not only a viable but also an attractive approach to inter-satellite link application. The high data rate and large information throughput available with Laser communications are many times greater than in radio frequency (RF) systems. The small antenna size requires only a small increase in the weight and volume of host vehicle. In addition, this feature substantially reduces blockage of fields of view of the most desirable areas on satellites. The smaller antennas, with diameters typically less than 30cm, create less momentum disturbance to any sensitive satellite sensors. Fewer onboard consumables are required over the long lifetime because there are fewer disturbances to the satellite compared with larger and heavier RF systems. The narrow beam divergence of affords interference-free and secure operation.In comparison to the radio frequency (FW) spectrum, the optical spectrum has the ability to provide unprecedented bandwidth capable of carrying huge amounts of data, outdoor wire less optical communications, conventionally known as Free Space Optics (FSO) communications hasbeen attracting increased attention as a broadband communications technology.