Patent ID: 7440168

Claim:
An optical transmission system comprising: a plurality of higher gain optical amplifiers, each having a higher nominal gain value across a plurality of optical signal channels; a plurality of lower gain optical amplifiers, each having a lower nominal gain value across said plurality of optical signal channels lower than said higher nominal gain value; a plurality of optical fiber spans coupling said optical amplifiers, wherein said higher gain optical amplifiers and said lower gain optical amplifiers are arranged to allow a net gain across said plurality of optical signal channels to vary within a predetermined acceptable net gain excursion at an output of each of said higher gain optical amplifiers and said lower gain optical amplifiers; and wherein a net gain vector in one direction through said optical fiber spans and said optical amplifiers is the same as a net gain vector in the other direction through said optical fiber spans and said optical amplifiers, said net gain vector being represented by values of net gain at outputs of said optical amplifiers, and wherein said net gain at a respective output of one of said optical amplifiers is the sum of cabled fiber losses at the respective output and nominal gains of said optical amplifiers at the respective output.