Patent ID: 8670176

Claim:
An optical amplifying device comprising: a first optical amplifier for amplifying signal light of a single wavelength; a second optical amplifier serially connected with the first optical amplifier; an optical device for compensating deterioration of the signal light, the optical device arranged between the first optical amplifier and the second optical amplifier; a variable optical attenuator for attenuating the signal light, the variable optical attenuator arranged between the first optical amplifier and the second optical amplifier; a first automatic level controller for detecting a second amplifier output power and for controlling driving status of the second amplifier to be a predetermined output power level in accordance with the detected second amplifier output power; and a first automatic gain controller for detecting an input power of the second optical amplifier and an output power of the second optical amplifier, and for controlling an optical attenuation value of the variable optical attenuator in accordance with the detected input power and output power of the second amplifier.