Evolution of 10.6 micron laser communication technology and comparison with alternate approaches

As projections for capacity of space data links continue to increase, attention is focusing on the more promising approaches to satisfy these requirements. Current trends are toward demonstration of 1 Gbs prototype links by the end of this decade. Because of the very long ranges involved and the physical limitations imposed by satellite burden constraints, large power-aperture products at short wavelengths offer the most promise. In the discussion to follow, the logical candidates at millimeter and laser wavelengths are considered in terms of their natural attributes, design trade-off issues, current status and projected applicability.