Patent ID: 6963681

Claim:
A method for providing dynamic gain control of an optical Raman amplifier in an optical communications link comprising an optical waveguide for transmitting optical signals on channels at different wavelengths, the optical Raman amplifier including at least a first optical pump source of a first pump wavelength and a second optical pump source of a second different wavelength, said pumps optically coupled to provide optical energy to the optical waveguide of sufficient pump powers to cause stimulated Raman scattering for amplifying optical signals, and a pump controller for controlling the pump powers of the at least first and second optical pumps in response to data from an optical signal detector at the output of the amplifier, comprising the steps of: a) characterizing a gain profile and gain level of the Raman amplifier when the channels of the communications link are fully loaded, over a wavelength spectrum at least as great as a desired transmission channel spectrum; b) pre-establishing a set of pump power values and signal level values required to maintain the characterized gain profile and gain levels for a plurality of channel loading configurations for the at least first and second pump wavelengths; c) deriving linear functions from the set of pre-established values for each of the at least first and second pump wavelengths; d) tapping a portion of an amplified signal; e) detecting a total amplified signal power from the tapped portion of the amplified signal; f) calculating the required first and second pump powers to maintain the characterized gain profile and gain level as a unique solution from the linear functions; and g) providing the calculated pump powers for the first and second pumps to a pump controller for comparing the calculated pump powers to current pump powers and varying the pump powers if necessary.