Patent ID: 7127166

Claim:
A method for transmitting at least one first and one second data signal in polarization division multiplex in an optical transmission system, the method comprising the steps of: generating a first modulated signal with a first transmission bit rate at a transmitting end by modulating a first carrier signal with the first data signal, using a nonreturn to zero coding; generating a second modulated signal with a second transmission bit rate by modulating a second carrier signal with the second data signal, using a return to zero coding; polarizing the first and second modulated signals mutually orthogonally; combining the polarized signals to form an optical multiplex signal; transmitting the optical multiplex signal; conducting the optical multiplex signal via a polarization control element at a receiving end to a polarization splitter; splitting the optical multiplex signal into the first and second modulated signals via the polarization splitter; converting the first modulated signal into a first electrical signal; converting the second modulated signal into a second electrical signal; determining a spectral component of at least one of the first and second electrical signals at a frequency corresponding to the first transmission bit rate; and deriving from the spectral component at least one control signal for controlling the polarization control element.