Method and apparatus for monitoring and correcting individual wavelength channel parameters in a multi-channel wavelength division multiplexer system

In a system and associated method for determining if a channel signal carried by a discrete wavelength channel (34, 36) is properly centered for that wavelength channel a signal generator (42) is provided that superimposes a secondary signal over the original signal in a signal channel. Tone detectors (52, 54) are provided at a point after the superimposition of the secondary signal. The tone detectors (52, 54) detect the superimposed tone signal at wavelengths that are longer and/or shorter than the wavelength assigned to the wavelength channel. By measuring (in 60) the degree of balance between wavelengths longer than the wavelength assigned to the wavelength channel and the wavelengths shorter than the wavelength assigned to the wavelength channel, it can be determined if the original signal is centered for that wavelength channel. If a predetermined degree of balance is not obtained, the original signal for the wavelength channel can be corrected or can be recognized as being non-compliant.