| 摘要 |
PURPOSE:To prevent obstruction due to a high optical power and the oscillation due to a reflected light fed back to the amplifier by detecting in increase in a reflected light from an open output terminal when no optical fiber is connected thereto and decreasing an output power of the optical amplifier via a gain control means. CONSTITUTION:When an output of an optical amplifier 1 is not connected to an optical fiber 2 being a transmission line, an increase in a reflected light from an open end 3 it detected by an optical detection means 4 and the result is given to a gain control means 5 to decrease output power of the optical amplifier 1. Thus, obstruction of a worker, at the site due to a high power when the output terminal of the optical amplifier is opened and the occurrence of the oscillation due to a reflected light fed back to the optical amplifier or the like are prevented. |
