Wireless optical communications via diversity reception and optical preamplification

Atmospheric optical communication systems that use optical preamplifiers and diversity reception to combat the effects of atmospheric turbulence are addressed. The effects of atmospheric turbulence, background light, source extinction ratio, amplified spontaneous emission, and receiver thermal noise are considered in the context of a semiclassical photon-counting approach. The particular diversity techniques that are investigated include aperture averaging, linear combining, and adaptive optics. Numerical results, obtained using a conditional Gaussian approximation, quantify the link margin improvement due to optical preamplification and diversity reception.