IN-BAND OSNR MONITOR WITH PMD INSENSITIVITY

摘要

An optical signal is processed so as to isolate at least one signal impairment for measurement, by exploiting whether or not signal elements arising from a given impairment exhibit statistical dependence between polarised signal components. The optical signal is split to produce first and second optical signal components which are distinctly polarised, e.g. orthogonally polarised. The first and second optical signal components are separately converted to the electrical domain to produce first and second electrical signal components. The first and second electrical signal components are processed to separate correlated signal impairment elements, such as PMD impairments, which are correlated between the first and second electrical signal components from uncorrelated signal impairment elements, such as ASE noise, which are uncorrelated between the first and second electrical signal components.