Abstract: A received POLMUX signal is rotated by fixed rotation parameters (Rot0, Rot1, Rot2) and the rotated POLMUX signal with optimal signal performance is selected and phase information is derived from both polarities. A pre-filter improves the timing accuracy.

Abstract: Disclosed herein is a dual parallel Mach-Zehnder-modulator (DPMZM) device comprising a DPMZM 10 having first and second inner MZMs arranged parallel to each other. The first inner MZM generates an in-phase component EI of an optical signal in response to a first driving voltage VI, and the second inner MZM generates a quadrature component EQ of said optical signal in response to a second driving voltage VQ. Further disclosed is a calculation unit 52 configured for receiving an in-phase component yI and a quadrature component yQ_ of a desired base-band signal, and for calculating pre-distorted first and second driving voltages VI, VQ. The calculation of the pre-distorted first and second driving voltages VI, VQ is based on a model of said DPMZM 10 accounting for I-Q cross-talk, and using an algorithm that determines said first and second driving voltages VI, VQ each as a function of both of said in-phase and quadrature components yI, yQ of said base-band signal.

Abstract: Component signal values are derived from component signals and fed to at least one fixed equalizer which generates equalizer output signals. The signals are fed to phase error detectors generating phase error signals. The phase error signals are combined with further phase error signals derived by further error detectors receiving signal values from further equalizers and/or the component signal values directly from sample units.

Abstract: Component signal values are derived from component signals and fed to at least one fixed equalizer which generates equalizer output signals. The signals are fed to phase error detectors generating phase error signals. The phase error signals are combined with further phase error signals derived by further error detectors receiving signal values from further equalizers and/or the component signal values directly from sample units.

Abstract: A method for phase recovery in a system that includes a clock recovery unit and an estimation unit. The clock recovery unit of the system has a first phase detector unit. The estimation unit has a second phase detector unit and it is configured to estimate a gain of the second phase detector unit. The estimation unit and the clock recovery unit are configured to operate in parallel.

Abstract: A method and device is provided for reducing optical transmission impairments, particularly nonlinear effects, of at least one link Said method comprising the following steps: extracting a phase information (??) from an optical signal (120) received via that at least one link, determining a nonlinear coefficient (?), associated with the at least one link, based on the phase information (??), applying a control mechanism (202) using the nonlinear coefficient (?). Furthermore, a communication system is suggested comprising said device.

Abstract: A method for processing data in an optical network element is provided, wherein a multicarrier signal is linear pre-coded, and wherein the linear pre-coded signal is modulated. An according optical network element is also suggested.

Abstract: A received optical signal is coherently demodulated and converted into electrical complex samples (p(n); (px(n), py(n)), which are dispersion compensated in a compensation filter (11). A control circuit (12, 13, 14, 15) calculates comparison values (R1, R2) from corrected samples q(n) and an estimated error value (?MIN). A plurality of compensation function (T(M)) is applied according to a predetermined dispersion (CD) range and after a second iteration is the compensation filter (11) set to an optimum compensation function (T(M)).

Abstract: Component signal values are derived from component signals and fed to at least one fixed equalizer which generates equalizer output signals. The signals are fed to phase error detectors generating phase error signals. The phase error signals are combined with further phase error signals derived by further error detectors receiving signal values from further equalizers and/or the component signal values directly from sample units.

Abstract: An apparatus for optical communication and optical communication method are provided, the method comprising the steps of generating an optical signal for transmitting the sequence of information data, transmitting the sequence of information data as a sequence of transmit matrices, S(k) being the k-th transmit matrix and k being a positive integer, and wherein the sequence of transmit matrices is transmitted through an optical channel characterized by a unitary channel matrix H, receiving a sequence of receive matrices, the k-th receive matrix R(k) being expressed as: R(k)=H·S(k)+N(k) wherein k is a positive integer and N(k) is a complex matrix of noise samples and providing a sequence of decision matrices, the k-th decision matrix D(k) being expressed as: D(k)=RH(k?1)R(k).

Abstract: A method and a device are provided for data processing. The data contains symbols and a control parameter is determined based on a correlation property of the symbols of the data. In this manner signal recovery is achieved that is robust against any kind of distortion and is fast enough to track time varying clocking disturbances. Further, a communication system is provided containing such a device.

Abstract: Component signal values are derived from component signals and fed to at least one fixed equalizer which generates equalizer output signals. The signals are fed to phase error detectors generating phase error signals. The phase error signals are combined with further phase error signals derived by further error detectors receiving signal values from further equalizers and/or the component signal values directly from sample units.

Abstract: A method and a device for processing a signal determine a timing phase over an observation interval of an input signal. A frequency estimation is determined based on the timing phase. A phase correction is determined for the observation interval based on the timing phase and the frequency offset. Then the phase correction is used to adjust the timing of the input signal. Also, a communication system with at least one such device is described.

Abstract: A received POLMUX signal is rotated by fixed rotation parameters (Rot0, Rot1, Rot2) and the rotated POLMUX signal with optimal signal performance is selected and phase information is derived from both polarities. A pre-filter improves the timing accuracy.

Abstract: A method for processing data in an optical network element is provided, wherein a multicarrier signal is linear pre-coded, and wherein the linear pre-coded signal is modulated. An according optical network element is also suggested.

Abstract: A received optical signal is coherently demodulated and converted into electrical complex samples (p(n); (px(n), py(n)), which are dispersion compensated in a compensation filter (11). A control circuit (12, 13, 14, 15) calculates comparison values (R1, R2) from corrected samples q(n) and an estimated error value (?MIN). A plurality of compensation function (T(M)) is applied according to a predetermined dispersion (CD) range and after a second iteration is the compensation filter (11) set to an optimum compensation function (T(M)).

Abstract: A method for processing data in an optical network element. A multi-carrier signal is linear pre-coded and the linear pre-coded signal is modulated. A corresponding optical network element is also described.

Abstract: A received optical signal is coherently demodulated and converted into electrical complex samples, which are dispersion compensated in a compensation filter. A control circuit calculates comparison values from corrected samples and an estimated error value. A plurality of compensation functions is applied according to a predetermined dispersion range and after a second iteration, the compensation filter is set to an optimum compensation function.

Abstract: A method and a device are provided for phase recovery of at least two channels comprising the steps of (i) a phase is estimated for each channel; (ii) the phase estimated of each channel is superimposed by a coupling factor with at least one other phase estimated. Further, a communication system is suggested comprising such a device.

Abstract: A method for phase recovery in a system that includes a clock recovery unit and an estimation unit. The clock recovery unit of the system has a first phase detector unit. The estimation unit has a second phase detector unit and it is configured to estimate a gain of the second phase detector unit. The estimation unit and the clock recovery unit are configured to operate in parallel.