Optical transmission systems including optical amplifiers and methods

A method of controlling the output wavelength of optical sources, comprising:

• providing at least first and second optical sources providing optical energy in corresponding first and second wavelength ranges;
• combining the optical energy provided by the first and second optical sources;
• providing the combined optical energy to an optical amplifying medium to amplify an optical signal passing through the amplifying medium;
• measuring optical noise in the combined optical energy in a frequency band;
• and,
• varying at least one of the first and second wavelength ranges to vary the optical noise in the combined optical energy in the frequency band and minimize beat noise produced by the first and second wavelength ranges.

A method of controlling the output wavelength of optical sources, comprising:

• providing at least first and second optical sources providing optical energy in corresponding first and second wavelength ranges;
• combining the optical energy provided by the first and second optical sources;
• providing the combined optical energy to an optical amplifying medium to amplify an optical signal passing through the amplifying medium;
• measuring optical noise in the combined optical energy in a frequency band;
• and,
• varying at least one of the first and second wavelength ranges to vary the optical noise in the combined optical energy in the frequency band and the frequency at which beat noise is produced by the first and second wavelength ranges.