| 摘要 |
An optical amplifier is disclosed, which comprises an optical amplifying unit for amplifying an optical signal, a light output monitoring unit for monitoring the light output of the optical amplifying unit, a control unit for controlling the optical amplifying unit by comparing the light output of the optical amplifying unit monitored by the light output monitoring unit with a specified reference value so as to cause the light output of the optical amplifying unit to take a predetermined output value and an input light level detecting unit for detecting the input light level of the optical signal. The control unit controls the light output level of the optical amplifying unit by changing the reference value used for comparison according to the input light level detected by the input light level detecting unit. By employing simple means for controlling the gain of the optical amplifying unit according to the input light level of the optical signal to be inputted, proper amplification control is performed without making the optical amplifier complex even when a change occurs in the number of input wavelengths. |
