| 摘要 |
PROBLEM TO BE SOLVED: To provide a device for optical amplification suitable for wavelength division multiplex WDM and a system including the device where a gain characteristics is maintained constant to obtain a wide input dynamic range and power of a pump light is reduced. SOLUTION: An optical amplification device includes 1st and 2nd optical amplifiers 6, 8, and a controller 22. The 1st optical amplifier amplifies a received light. The 2nd optical amplifier receives the light amplified by the 1st optical amplifier and amplifies the amplified light. The controller 22 controls an attenuator 10 so that a level of the light received by the 2nd optical amplifier is changed nearly by -Δ when the level of the light received by the 1st optical amplifier changes by Δ. In one of various embodiments, the controller controls a sum of the gains of the 1st and 2nd optical amplifiers to be constant. In the other embodiment, the optical amplification device includes the 1st and 2nd optical amplifiers and a gain adjustment device. The gain adjustment device adjusts the gain of the 2nd optical amplifier to compensate a deviation between the gain of the 1st optical amplifier and an objective gain. |
