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 Optical Line Terminal (OLT) transmitting device is provided, the device comprising an IQ modulator having a first input, a second input and an output, a first digital analog converter (DAC) directly coupled to the first input of the IQ modulator, a second digital analog converter (DAC) directly coupled to the second input of the IQ modulator; an optical filter directly coupled to the output of the IQ modulator.

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: An optical network unit has a tunable laser. The tunable laser is tunable such that a point-to-point connection to another optical network unit is established via an optical fiber. There is also provided a method for processing data in an optical network and a corresponding communication system. The tunable laser can be adjusted based on a detected collision, and a frequency grid can be supplied from a centralized component.

Abstract: The present invention provides an apparatus, in particular an optical network unit, which comprises a first part operably coupled to an arm of an optical fiber network, the first part comprises an optical module including an optical-electric interface and/or an electric-optical interface locked on a preset wavelength band, and an interface module, and at least one second part operably coupled to a network entity of a communication network, each comprising a control unit, a signal processing unit and an interface module. One of the control units of the at least one second part is set by a optical line terminal of the optical fiber network as a master control unit configured to tune and control the optical module of the first part. The first part and the at least one second part are wireless coupled with respect to each other via the interface modules.

Abstract: Safety and power control arrangement and method for optical communication apparatus, where a first circuit pack emitting an optical signal (OS1) and at least a second and a third circuit pack (2, 3) are connected in series via optical fibers (4, 5). A power monitor (26) connected to an output (27) of the at least second circuit pack (2) reduces the signal power (PW2) output from the second circuit pack (2) to a pre-determined safe value if a loss-of signal monitor (34) of a next circuit pack (3) forwards a loss-of-signal control signal (LOC3). The advantage is that the maximum allowable value is achieved at the input of an interrupted fiber section and the non-interrupted circuits can still receive the optical signals with a reasonable power level.

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: An optical network component is provided comprising a semiconductor optical amplifier with an input and an output, wherein the input is connected to a light source, wherein the output is connected to an amplitude modulator, wherein the semiconductor optical amplifier converts an amplitude modulated signal from the amplitude modulator to a phase modulated signal and provides the phase modulated signal at its output. Also, a transmitter comprising at least one such optical network component is suggested.

Abstract: A method and devices for processing data in an optical network are provided, wherein a centralized component is connected to several decentralized components; wherein first data is conveyed from the centralized component to at least two decentralized components, wherein at least two decentralized components share an optical resource; and wherein second data is conveyed from the decentralized component to the decentralized component via at least one separate optical resource. Furthermore, a communication system is suggested comprising said device.

Abstract: A method and a device for adjusting a laser in an optical network. At least one alive message is transmitted from a first optical component towards a second optical component. A confirmation message is transmitted from the second optical component to the first optical component determining the wavelength of the laser to be used based on the alive message received by the second optical component. Furthermore, an optical communication system is provided with an optical element.

Abstract: The invention refers a method and an arrangement for channel set up in an optical network. An optical signal path is configured for a certain optical channel signal (OC1) of a WDM-signal. This channel signal (OC1) is on-off-modulated by a modulation test signal (MT1) having a predetermined lower frequency and is generating a channel test signal (OT1). This channel test signal (OT1) is combined with other optical channels (OC2-OCn) to the WDM-signal (WS) and transmitted via said path. At a start node (1) or a downstream node (3, 5) a measurement signal (EMI, EM3) is derived from the complete WDM-signal (WS) without wavelength de-multiplexing. The measurement signal (EMI, EM3) is compared with a correlation signal (MC1) and an obtained power level (PC1) is used to adjust the channel power (PC1, PC2, PC3) to achieve predetermined target power values (PC1-PC4) at different power monitoring points (19, 40, 41, 58).

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 for controlling a variation in gain in an optical amplifier stage and an optical amplifier. The optical amplifier stage includes a pumping device for providing pumping power and a control unit for determining a change in an input power of the optical amplifier. The method includes the steps of determining a change in an input power of the optical amplifier, adjusting a pumping power of the pumping device to a first power level for a predetermined period of time and adjusting the pumping power of the pumping device to a second power level. The second power level is able to drive the amplifier gain to a predetermined gain value after the change in the input power occurred.

Abstract: A first optical data signal is transmitted on a first data carrier from a first network element. First service information is transmitted from a first service by means of a first optical service signal on a first service carrier. A second optical data signal is transmitted on a second data carrier from a second network element, and second service information is transmitted by a second optical service signal on a second service carrier. An offset between a frequency of the first data carrier and a frequency of the first service carrier is substantially equal to an offset between a frequency of the second data carrier and a frequency of the second service carrier.

Abstract: A method for processing data in an optical network element are provided, wherein the optical network element comprises a local oscillator operating at a first frequency; wherein an incoming data stream is received at a second frequency; wherein the incoming data steam is processed using the first frequency; wherein a first pattern is searched in the incoming data stream; wherein a second pattern is searched in the incoming data stream; and wherein the first pattern corresponds to the first frequency being in the spectrum on one side of the second frequency and the second pattern corresponds to the first frequency being in the spectrum on the other side of the second frequency. Also, a corresponding optical network element and a communication system comprising at least one such optical network element are suggested.

Abstract: An optical component contains a tunable laser. The tunable laser provides an optical local oscillator signal, and the tunable laser is directly modulated to provide a modulated optical data signal. In this manner we have optimization of the channel wavelength and obtain an optimized electrical and optical bandwidth utilization. Furthermore, a method for data processing is suggested.