Patent ID: 8494373

Claim:
An apparatus for compensating polarization mode dispersion for an optical transmission fiber for transmission of optical signals, said optical signals having a modulation format using a first polarization component and an orthogonal second polarization component comprising: tuneable means adapted to compensating said fiber polarization mode dispersion; a feedback signal generator adapted to generating a feedback input signal for said tuneable means for polarization mode dispersion compensation, wherein said feedback signal generator comprises polarization means for converting said transmitted optical signal to at least two optical signal components with different defined non-orthogonal states of polarization, transforming means for transforming said optical signal components into electrical signal components, wherein each electrical signal component represents one of said defined non-orthogonal states of polarization, at least one mixer for mixing at least two of said electrical signal components to mixed electrical signals, means for averaging said electrical signal components to average electrical signals and averaging said mixed electrical signals to average mixed electrical signals, means for combining said average electrical signals and said average mixed electrical signals to generate said feedback input signal which is characteristic for a digital group delay of said transmission signal caused by said polarization mode dispersion.