Patent ID: 7355786

Claim:
A Raman amplifying device including a plurality of Raman amplifiers having a gain wavelength characteristic with a gain peak at which an amplification gain becomes the largest, the Raman amplifying device comprising: at least one Raman amplifier having a first gain characteristic; at least one Raman amplifier having a second gain characteristic shifted from the first gain characteristic by a shift amount determined based on a periodic distribution obtained from sum approximation of periodic functions with respect to the first gain characteristic; an amplification gain controller that controls the gain wavelength characteristics of the Raman amplifiers based on an intensity wavelength characteristic of a light amplified by the Raman amplifiers, wherein the amplification gain controller includes a wavelength detector that selects a Raman amplifier having a gain peak closest to a wavelength of a wavelength component whose light intensity is deviated from a predetermined tolerance in the light amplified, and the amplification gain controller controls the gain wavelength characteristics of the Raman amplifiers in such a manner that the intensity of the light amplified is suppressed to within the tolerance by changing at least one of the wavelength of the predetermined gain peak and the peak intensity of the Raman amplifier selected.