Patent ID: 6876489

Claim:
A Raman amplifier apparatus, comprising: an optical transmission line including an input operable to receive an optical signal comprising a plurality of optical signal wavelengths, an output operable to pass at least a portion of the optical signal, a first Raman gain fiber and a second Raman gain fiber; a first optical coupler positioned between the second Raman gain fiber and the output, wherein a first plurality of pump wavelengths is input to the first optical coupler, and wherein at least two of the first plurality of pump wavelengths comprise different center wavelengths; and a second optical coupler positioned between the first and second Raman gain fibers, wherein a second plurality of pump wavelengths is input to the second optical coupler, and wherein at least two of the second plurality of pump wavelengths comprise different center wavelengths; wherein at least a portion of the first plurality of pump wavelengths comprise different center wavelengths than the second plurality of pump wavelengths, wherein the first and second pluralities of pump wavelengths propagate in a same direction and wherein a majority of shorter optical signal wavelengths receive more gain in the second Raman gain fiber than in the first Raman gain fiber.