A Raman amplifier is provided that includes at least a portion of optical fiber in which an optical signal travels. The optical fiber portion may encompass all or part of the optical transmission path of an optical communication system. A pump energy unit is provided that includes at least three pump sources providing pump power at different pump wavelengths. The different pump wavelengths are spaced apart from one another by nonuniform amounts so that a prescribed Raman gain profile is generated in the optical fiber portion. An optical coupler is provided for coupling the pump power to the optical fiber portion and transmitting the optical signal therethrough.