| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an optical amplifier which is composed of a plurality of cascade connected amplifier units, each including an exiting light source and an amplifying optical fiber and restrains the total transient gain variation. <P>SOLUTION: The optical amplifier 1 comprises amplifier units 1A, 1B, a variable optical attenuator 1C, and control circuits 19A, 19B. The amplifier unit 1A optically amplifies a signal light inputted thereto on an amplifying optical fiber 11A after passing through a branch coupler 16A and a combining coupler 15A and outputs it to the variable optical attenuator 1C via a branch coupler 17A. The signal light outputted from the amplifier unit 1A is attenuated by the attenuator 1C and then inputted to the amplifier unit 1B. The amplifier unit 1B optically amplifies the signal light inputted thereto on an amplifying optical fiber 11B after passing through a branch coupler 16B, a delaying optical fiber 18B and a combining coupler 15B and outputs it from the amplifier unit 1B via a branch coupler 17B. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
