| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical amplifier that provides an output of an alarm selecting either one of a decreased input signal optical level, deterioration in a stimulation light source, or deterioration in optical passive components of the optical amplifier. SOLUTION: An output light control circuit 12 controls a drive current of a stimulation light source 10 based on an output signal optical level from an output optical monitor receiver 8 and provides an output of a stimulated current to an alarm circuit 13. A stimulation light monitor receiver 11 provides an output of a stimulation light level in the stimulation light source 10 to the alarm circuit 13. An input light monitor receiver 7 provides an output of an input signal optical level from an optical branching device 2 to the alarm circuit 13. The alarm circuit 13 monitors each operating state of the stimulated current, the stimulated optical level and the input signal optical level and provides an output of a stimulation light source deterioration alarm, an optical passive component deterioration alarm and an input signal optical level deterioration alarm depending on the monitored result. |
