Fiber optic communication generally comes to mind first when one thinks or speaks of optical communication. In fact, the two terms are often used synonymously. Indeed, the fiber optic communication technology is maturing rapidly and it offers enor-mous advantages over unguided atmospheric optical propagation systems. However, there is a variety of applications for which fiber systems are impractical and for which atmospheric optical systems may be preferred. For example, short-haul, over-the-horizon links in areas where cable real estate rights are unobtain-able, or where an optical broadcast mode is desired, or for space-to-earth optical links.