Optical instruments have long been used in space, in scientific and observation satellites. On the other hand, telecommunication satellites were and are the realm of RF/microwave techniques. But, in 1981, a new era began when the first flight model satellite-to-satellite optical crosslink was ordered by the U.S. Government. At that time, strategic reasons (no reliance on foreign ground stations, survivability, etc.) were probably as important as technical reasons.
Information courtesy of "Laser and Electro-Optics Society, 1998."