| 摘要 |
PROBLEM TO BE SOLVED: To suppress an optical surge effectively by an arrangement wherein an optical amplifier comprises a medium for amplifying and outputting input light and a member for reflecting light of specified wavelength other than that of a signal contained in the input light is disposed on the input side and output side of the amplifying medium. SOLUTION: The optical amplifier 20 comprises an isolator 21, a branch unit 22 for an input monitor, a WDM coupler 23, an optical amplifying medium 24, a fiber grating 25 and an isolator 26. A fiber grating 28 is disposed on the input side of the optical amplifying medium 24 through the WDM coupler 23, the branch unit 22 for the input monitor and an optical variable attenuator 27 and a fiber grating 25 is disposed on the output side of the optical amplifying medium 24. The fiber gratings 25, 28 function as a member for reflecting a light of specified wavelength other than that of a signal contained in the input light. Consequently, the input vs gain characteristics can be regulated to suppress optical surge. |
