Patent ID: 7620326

Claim:
A method for transmitting a first and a second data signal as a polarization multiplex signal in an optical transmission system, comprising: modulating at the transmitting end the first data signal onto a first optical carrier signal and generating a first single sideband modulated signal; modulating at the transmitting end the second data signal onto a second optical carrier signal, which has the same optical carrier frequency or even differs by a differential frequency (Δf) from the first carrier frequency, and generating a second single sideband modulated signal such that the spectra of the first and the second sideband modulated signals overlap, by which means the transmission bandwidth is reduced; orthogonally polarizing the first and the second sideband modulated signals to each other; combining the first and the second sideband modulated signals into the optical polarization multiplex signal with overlapping orthogonal spectra including both optical carriers; transmitting the optical polarization multiplex signal; feeding at the receiving end the transmitted optical polarization multiplex signal via a polarization control element to a polarization splitter, which separates the optical polarization multiplex signal into the first and the second sideband modulated signals; converting the first sideband modulated signal to a first electrical signal and converting the second sideband modulated signal to a second electrical signal; analyzing at least one of the first and the second electrical signal; and dependent on the analyzing result, deriving at least one control signal for controlling the polarization control element.