A performance monitoring method for an optically amplified transmission system.
The method provides the optical power at each amplifier site, taking into account
the inaccuracies introduced by the SRS in the power estimation obtained with the
current methods. An optical spectrum analyzer is used at the output of the transmission
link of interest to accurately measure the output power of each wavelength. This
value is sent upstream to the last amplifier in the link, to compute an error term
as the difference between the actual measurement and the estimation. The error
term is used to infer the SRS-induced error by system elements not accounted for
in the model. The error term is then fed-back to each amplifier in the link, so
that the estimated power is adjusted to account for the SRS-induced inaccuracy.
