| 摘要 |
PROBLEM TO BE SOLVED: To provide a free space optical communication system wherein the reception power at a reception optical fiber is reduced by mutually adjusting so that a transmitted optical beam and the reception optical fiber cross each other not at the focal point of the transmitted beam but at a divergent point when a specified power threshold is exceeded. SOLUTION: The transmitted beam is diverged by moving a transmission optical fiber to a point before the focal plane of a transmission telescope along the length axis of the telescope until at least a part of the beam is incident on the reception optical fiber. As a result, the beam enlarges the cross-sectional area of the point where the beam is incident on the reception telescope. Thus, the cross-section electric power per unit area of the transmitted beam reduces, and the power which is incident on the reception optical fiber is reduced accordingly. |
