Xieon Networks S.a.r.l.

Huawei Technologies Co., Limited

Nokia Siemens Networks Gmbh & Co Kg

Nokia Solutions and Networks Gmbh & Co. Kg

Stefano Calabro

Bernhard Spinnler

Changsong Xie

Maxim Kuschnerov

Christina Hebebrand

Erich Gottwald

Berthold Lankl

Antonio Napoli

Ernst-Dieter Schmidt

Alessandro Bianciotto

Nancy Hecker

Werner Rosenkranz

Mahdi Mezghanni

Fabio Pittala

Stephan Witte

Jinlong Wei

Maximilian Schaedler

Georg Sebald

Peter Kainzmaier

Thomas Michaelis

Heinrich Von Kirchbauer

Miguel Drummond

Ivan Nicolas Cano Valadez

Christian Blümm

Constanze Hantschmann

Giuseppe Talli

The present disclosure relates to a digital filter arrangement (DFA) for compensating group velocity dispersion (GVD) in an optical transmission system (OTS) wherein the DFA is configured to receive a sequence of samples of a digital input signal in the time domain in the form of consecutive blocks of size L. The DFA is configured to generate M discrete Fourier transforms of a current overlap block of a size N greater than the size L and of M−1 delayed versions of the current overlap block. The DFA is configured to filter the entries of the generated M discrete Fourier transforms to generate an output discrete Fourier transform with N entries, wherein the compensation filter is implemented by a delay network and a linear combination algorithm.

Digital filter arrangement for compensating group velocity dispersion in an optical transmission system

A method for optical communication between transceivers through an optical link for chromatic dispersion pre-compensation, includes generating and sending, by a second transceiver, a first CD pre-compensated optical signal and a second CD pre-compensated optical signal, to the first transceiver through the optical link. The method further includes receiving, by a first transceiver, the first and second CD pre-compensated optical signals, and calculating a first residual chromatic dispersion (RCD) value from the received first CD pre-compensated optical signal, and a second RCD value from the received second CD pre-compensated optical signal. The method further includes calculating, by the first transceiver, a third PCD filter using the first RCD value, and a fourth PCD filter using the second RCD value. The third PCD filter and the fourth PCD filters are used to generate and send two CD pre-compensated optical signals to the second transceiver, which provides tunable CD pre-compensation capability.

Chromatic dispersion pre-compensation over bi-directional optical link

A transmitting device configured to obtain a message to be transmitted; map the obtained message onto a two-dimensional 2-symbol constellation to obtain a sequence of discrete constellation symbols, where n is an odd number not less than 3. A receiving device configured to receive a sequence of noisy discrete constellation symbols; demap the sequence of noisy discrete constellation symbols to output data using a two-dimensional 2-symbol constellation, where n is an odd number not less than 3.

Class of symbol constellations for data transmission

Enclosed herewith is a method for protecting a link in an optical network configured for transmitting digital data employing a predetermined modulation format which comprises a number of symbols in a constellation diagram. A binary address is associated with each symbol. The modulation format allows for a constellation distortion, according to which the relative positions of constellation points in the constellation diagram are varied in a predetermined way by a predetermined degree. The method the steps of: A) partitioning the traffic in two or more priority classes, B) mapping higher priority traffic to predefined bit positions within the binary symbol addresses, C) evaluating the quality of a predetermined protection link, D) determining a degree of distortion such that a desired transmission quality for the transmission of the traffic of the highest priority class or classes via said predetermined protection link and a desired transmission quality for the full traffic via said given link are simultaneously ensured, and E) employing said distorted constellation diagram for transmission of digital data over said given link.

Method for protecting a link in an optical network

The present invention relates to signal processing in an optical receiver, in particular to equalization performed in coherent optical receivers. A multiple-input multiple-output (MIMO) equalizer receives and equalizes a plurality of real value signals, for example four sampled electrical baseband tributaries (HI, HQ, VI, VQ). The outputs of the multiple-input multiple-output (MIMO) equalizer provide equalized real or imaginary components of complex signals. The complex signals including the real and imaginary components are then each and individually equalized to remove chromatic dispersion.

Signal processing in an optical receiver

Disclosed herein is a dual parallel Mach-Zehnder-modulator (DPMZM) device comprising a DPMZMhaving first and second inner MZMs arranged parallel to each other. The first inner MZM generates an in-phase component Eof an optical signal in response to a first driving voltage V, and the second inner MZM generates a quadrature component Eof said optical signal in response to a second driving voltage V. Further disclosed is a calculation unitconfigured for receiving an in-phase component yand a quadrature component yof a desired base-band signal, and for calculating pre-distorted first and second driving voltages V, V. The calculation of the pre-distorted first and second driving voltages V, Vis based on a model of said DPMZMaccounting for I-Q cross-talk, and using an algorithm that determines said first and second driving voltages V, Veach as a function of both of said in-phase and quadrature components y, yof said base-band signal.

Dual parallel Mach-Zehnder-modulator device with pre-distorted driving voltages

Disclosed is a method for decoding an optical data signal. Said optical data signal is phase and amplitude modulated according to a constellation diagram with at least eight constellation points representing non-binary symbols. Said decoding method comprises the following steps: &#x2014;carrying out a carrier phase recovery of a received signal ignoring the possible occurrence of phase slips, &#x2014;decoding said signal after phase recovery, wherein in said decoding, possible cycle slips occurring during phase recovery are modelled as virtual input to an equivalent encoder assumed by the decoding scheme. Further disclosed are a related encoding method as well as a receiver and a transmitter.

Cycle slip resilient coded modulation for fiber-optic communications

An encoder encodes digital data, said encoder includes one or more component encoders, one or more interconnections between component encoders, one or more inputs and one or more outputs. The encoder is configured to carry out the following steps: combining internal input bits received via an interconnection and external input bits received via a corresponding input, to assemble a local information word, encoding the local information word such as to generate a local code word, outputting a reduced local code word and handling the same reduced local code word over to the interconnect for forwarding the same reduced local code word to another component encoder or to itself, wherein the encoder is configured to forward on each interconnect the bits of the reduced local code in parallel but with delays that are mutually different for at least a subset of the reduced local code word bits.

Encoder, decoder and encoding method with low error floor

The present invention relates to performing chromatic dispersion estimation in a receiver of an optical communication system. Here, the signal received by the receiver includes frames, each comprising a training portion and a data portion. The training portion comprises a plurality of identical pattern sequences. Different settings are applied to an equalizer to generate a plurality of equalized signals from at least one of the received frames. Then, at least one correlation value is calculated between a first pattern sequence and a second pattern sequence of the equalized signals and a final correlation value is derived from the respective correlation values. The setting of the equalizer corresponding to the equalized signal providing the highest final correlation value is selected to provide the chromatic dispersion estimation.

Data-aided chromatic dispersion estimation

Disclosed herein is a modulator () for polarization-division multiplexing (PDM) transmission. The modulator () comprises first and second DP-MZMs () associated with first and second polarizations, each DP-MZM () having an input for an in-phase and a quadrature driving signal for modulating the in-phase and quadrature components of an optical signal according to respective transfer functions, and a detector () suitable for detecting light comprising at least a portion of the light outputted by the first DP-MZM () and a portion of the light outputted by the second DP-MZM (). The modulator () is adapted to superimpose a first pilot signal on one of the in-phase and quadrature driving signals of the first DP-MZM () and on one of the in-phase and quadrature driving signals of the second DP-MZM (), and a second pilot signal on the respective other of the in-phase and quadrature driving signals of the first and second DP-MZMs (). Further, the first and second pilot signals are chosen such that the signal detected by said detector () is indicative as to whether the slopes of the transfer functions are different for the in-phase and quadrature components of one of the first and second DP-MZMs () and identical for the other of the first and second DP-MZMs ().

Spectral inversion detection for polarization-division multiplexed optical transmission

A received POLMUX signal is rotated by fixed rotation parameters (Rot, Rot, Rot) 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.

Symbol timing estimation for coherent polarization multiplex optical receivers

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.

Method and system for clock recovery with adaptive loop gain control

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&#xb7;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)=R(k&#x2212;1)R(k).

Optical communication apparatus and method

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.

Optical communication method and system

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.

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Munich, Germany

Stefano Calabro