Abstract: A transparent optical overlay network (1) for providing end-to-end optical spectrum services over multiple transparent optical network domains (2) is described. The transparent optical overlay network (1) includes network domain interface devices, NDIDs, (3) provided at domain boundaries between adjacent transparent optical network domains (2). The network domain interface device, NDID (3), monitors and adjusts incoming optical signals received by the NDID (3) from a first transparent optical network domain (2-1) and monitors and adjusts outgoing optical signals output by the NDID (3) to an adjacent second transparent optical network domain (2-2). An overlay network controller (5) manages and controls the end-to-end optical spectrum services by controlling the NDIDs (3). The overlay network controller collects telemetry data (TDATA) for optical spectrum service characterization and SLA policing of the optical spectrum services.

Abstract: A first and second head-end terminal and at least one optical add/drop filter device are connected to form a transmission path. Each head-end terminal is connected through an optical fiber to a western or eastern WDM port of an adjacent optical add/drop filter device, and each optical add/drop filter device is connected, at an eastern or western WDM port, to a western or eastern WDM port of an adjacent optical add/drop filter device. At least one tail-end terminal is connected to each optical add/drop filter device, wherein a first and second channel port of the respective add/drop tail-end terminal is connected to a dedicated first and second channel port of the optical add/drop filter device through a respective optical fiber. The head-end terminals, the optical add/drop filter devices, and the tail-end terminals are adapted to establish bidirectional communication between each tail-end terminal and the first and second head-end terminal.

Abstract: An optical WDM transmission system including a plurality of first optical transceivers at a first end of an optical WDM transmission link, each including a tunable optical transmitter being adapted to create a first digital optical channel signal within the bandwidths of a set of first optical channels of the system according to tuning control information. The first channels are multiplexed in to a first WDM signal and supplied at the first end of the WDM link. Second optical transceivers at a second end link each include a transmitter adapted to create a second digital optical channel signal within a channel bandwidth of a second set of optical channels of the system. The second channels are multiplexed into a second WDM signal for transmission to the first transceivers, and demultiplexing there.

Abstract: A method for bi-directionally transmitting digital optical signals over an optical transmission link in which a first optical transmit signal is created according to a first binary digital signal in such a way that the bit information of the first binary digital signal is included in first sections of the symbol interval of the first optical transmit signal. A second optical transmit signal is created by creating an optical wavelength reuse signal using the first optical transmit signal received at the second end of the optical transmission link, the optical wavelength reuse signal being modulated according to a second digital signal in such a way that the bit information of the second digital signal is included in second sections of the symbol interval of the first optical transmit signal received.

Abstract: An optical transmission system method including generating for a tunable laser a pilot tone having an adjustable pilot tone frequency identifying a wavelength division multiplexing channel used by the tunable laser; multiplying the pilot tone with pilot tone data to provide a pilot tone data signal; supplying the pilot tone data signal and a high frequency data signal to the tunable laser generating an optical laser signal output by the tunable laser responsive to the supplied signals; transporting the optical laser signal to a central wavelength to locker; converting the received optical laser signal to provide a pilot tone data signal for wavelength division multiplexing channels demodulated to detect the pilot tone and the pilot tone data for each individual wavelength division multiplexing channel; and identifying the wavelength division multiplexing channel on the basis of the pilot tone frequency of the detected pilot tone and evaluating the pilot tone data.

Abstract: The invention relates to a method for the transmission of a digital signal in inverse multiplexing, particularly via an Optical Transport Network (OTN), in which a digital signal to be transmitted, which is split into a certain number M of several sub-signals, where each sub-signal of a transmit side of a transmission line assigned exclusively to this sub-signal is transmitted to a reception side of the assigned transmission line, and in which, on the reception side of the transmission lines, the sub-signals are reassembled to a digital reception signal.

Abstract: A method for bi-directionally transmitting digital optical signals over an optical transmission link in which a first optical transmit signal is created according to a first binary digital signal in such a way that the bit information of the first binary digital signal is included in first sections of the symbol interval of the first optical transmit signal. A second optical transmit signal is created by creating an optical wavelength reuse signal using the first optical transmit signal received at the second end of the optical transmission link, the optical wavelength reuse signal being modulated according to a second digital signal in such a way that the bit information of the second digital signal is included in second sections of the symbol interval of the first optical transmit signal received.

Abstract: The invention relates to an optical WDM transmission system including a plurality of first optical transceivers (11) at a first end (7) of an optical WDM transmission link (5, 5?), each of the first optical transceivers (11) including a tunable optical transmitter (17) being adapted to create a first digital optical channel signal (S1ch,i) within the bandwidths of a set of first optical channels of the optical WDM transmission system (1, 1?) according to a tuning control information, multiplexing means (13) for multiplexing the first digital optical channel signals (S1ch,i) into a first optical WDM signal (S1WDM), which is supplied to the first end (7) of the optical WDM transmission link (5, 5?), a plurality of second optical transceivers at a second end (9) of the optical WDM transmission link, each of the second optical transceivers including an optical transmitter being adapted to create a second digital optical channel signal (S2ch,i) within the bandwidth of a predetermined optical channel of a second se

Abstract: The invention relates to a protected optical single-fiber WDM system. A first (3) and a second (5) head-end terminal and at least one optical add/drop filter device (11) are connected to form a chain-like transmission path, each of the first and second head-end terminals (3, 5) being connected, at a WDM port (3a, 5a), through a single optical fiber (13) to a western (11a) or an eastern WDM port (11d) of an adjacent one of the optical add/drop filter devices (11), respectively, and each of the optical add/drop filter devices (11) being connected, at an eastern or western WDM port (11d, 11a), to a western or eastern WDM port (11a, 11d) of an adjacent one of the optical add/drop filter devices (11), respectively.

Abstract: The present invention embraces an optical wavelength division multiplex (WDM) transmission system, especially a WDM passive optical network, typically including a central node having a first and a second WDM port and a remote node having a first and a second WDM port and a plurality of channel ports, the central node first WDM port being connected to the remote node first WDM port via a bidirectional single-fiber optical working path and the central node second WDM port being connected to the remote node second WDM port via a single-fiber bidirectional optical protection path, and a group of basic optical node units (ONU's) each of which is connected to a respective remote node channel port via a bidirectional optical ONU path, each ONU including an optical receiver for receiving a downstream optical channel signal and an optical tunable transmitter for creating an upstream channel signal.

Abstract: A receiving apparatus and method for processing a differential phase shift keying signal carrying a plurality of symbols are disclosed to provide for improved compensation of linear and non-linear noise in phase modulated optical transmission. The receiving apparatus comprises an input unit for receiving electrical signals derived from an optical signal and a calculation unit for calculating a current value of a decision variable. The current value is indicative of a differential phase shift in the optical signal between a currently received symbol and a previously received symbol as a function of the optical signal power of the optical signal for the currently received symbol and at least one previous value of the decision variable. The receiving apparatus also comprises a decision unit for determining the differential phase shift from the current value of the decision variable obtained from the calculation unit to obtain the currently received symbol.

Abstract: The present invention embraces an optical wavelength division multiplex (WDM) transmission system, especially a WDM passive optical network, typically including a central node having a first and a second WDM port and a remote node having a first and a second WDM port and a plurality of channel ports, the central node first WDM port being connected to the remote node first WDM port via a bidirectional single-fiber optical working path and the central node second WDM port being connected to the remote node second WDM port via a single-fiber bidirectional optical protection path, and a group of basic optical node units (ONU's) each of which is connected to a respective remote node channel port via a bidirectional optical ONU path, each ONU including an optical receiver for receiving a downstream optical channel signal and an optical tunable transmitter for creating an upstream channel signal.

Abstract: The invention relates to a method for the transmission of a digital signal in inverse multiplexing, particularly via an Optical Transport Network (OTN), in which a digital signal to be transmitted, which is split into a certain number M of several sub-signals, where each sub-signal of a transmit side of a transmission line assigned exclusively to this sub-signal is transmitted to a reception side of the assigned transmission line, and in which, on the reception side of the transmission lines, the sub-signals are reassembled to a digital reception signal.

Abstract: A receiving apparatus and method for processing a differential phase shift keying signal carrying a plurality of symbols are disclosed to provide for improved compensation of linear and non-linear noise in phase modulated optical transmission. The receiving apparatus comprises an input unit for receiving electrical signals derived from an optical signal and a calculation unit for calculating a current value of a decision variable. The current value is indicative of a differential phase shift in the optical signal between a currently received symbol and a previously received symbol as a function of the optical signal power of the optical signal for the currently received symbol and at least one previous value of the decision variable. The receiving apparatus also comprises a decision unit for determining the differential phase shift from the current value of the decision variable obtained from the calculation unit to obtain the currently received symbol.

Abstract: A WDM optical cross-connect has input and output channels for through traffic. A first group of matrices connects the input channels to the output channels. Each input channel is connected to an input of a matrix of the first group and each output channel is connected to an output of the matrix. Input/output channels are provided for adding/dropping traffic. Each add/drop channel is connected to an input/output of a second group of matrices. The outputs/inputs of the second group of matrices are connected to inputs of a third group of matrices or outputs of a fourth group of matrices and the outputs/inputs of the third/fourth group of matrices are connected to inputs/outputs of the first group of matrices such that the matrices of the second, third and first groups of the first, fourth and second groups each form a Clos network.

Abstract: A node for an optical communication network comprises at least one switching unit (2), a plurality of optical interfaces (1) for connecting to a WDM transmission line (3), which comprise a demultiplexer (4) for disassembling a multiplex signal arriving from a WDM transmission line (3) into a plurality of input channels (8), each of which is supplied to an input port of the switching unit (2), and a multiplexer (5) for assembling a plurality of output channels (11), each originating from an out-put port of the switching unit (2), into an outgoing multiplex signal, and at least one transponder (6) for adding an information signal to and dropping it from the communication network, respectively.

Abstract: A method is provided for determining and setting the tilting of the spectrum of light signals in an optical fiber of an optical data transmission path having at least one part for varying the tilting of the spectrum, wherein the light signals are amplified by at least one optical amplifier and a portion of the amplified light signals is extracted, the extracted light signals are then partially guided through an influencing element with a known frequency-dependent intensity influence, the influencing element being an amplifier, a waveguide structure or a fiber with an amplifying action, the total intensity of the extracted light signals is then measured upstream and downstream of the influencing element prior to the extracted light signals being guided through the influencing element, and the control criterion is determined, based on the known frequency-dependent intensity influence of the influencing element and the measured total intensity, for setting the tilting via which the part for varying the tilting i

Abstract: A method and device are provided for measuring the non-linear coefficient and/or the dispersion coefficient of an optical fiber in an optical data transmission path by four-wave mixing, wherein at least two pump signals of known intensity with at least two different input frequencies are injected into one end of an optical fiber to be measured, in order to obtain at least two signals with at least two new frequencies by four-wave mixing, with the intensity of the backscattered signals of the new frequencies being measured at the feed side and the non-linear coefficent and/or the dispersion coefficient being determined from the measured intensities.

Abstract: An optical switching station comprises a first plurality of input channels for through data traffic, a second plurality of output channels for through data traffic, at least one first optical switching matrix comprising a first group of input connectors connected to the input channels on the switching station and a first group of output connectors connected to the output channels on the switching station, for connecting the input channels and the output channels to each other, and a group of one or more signal shaping units, each of a second group of output connectors being connected with an input of a signal shaping unit belonging to the group and each of a second group of input connectors being connected with an output from one of the signal shaping units.

Abstract: A wavelength division multiplex (WDM) optical cross-connect (OXC) has a plurality (N×M) of input and output channels (iI to iM; o1 to oM) for through traffic. A first group of optical switching matrices (SI-I to SI-N) is provided for connecting the through traffic input channels (iI to iM) to the output channels (o1 to oM), wherein each through traffic input channel (iI to iM) is connected to an input of a switching matrix (SI-I to SI-N) of the first group and each through traffic (o1 to oM) is connected to an output of the switching matrix (S1-1 to S1 -N). Additionally a plurality (P) of input channels (a1 to aP) and/or output channels (o1 to oP) is provided for adding/dropping traffic. Each add/drop input/output channel (a1 to aP, o1 to oP) is connected to an input/output of a second group of switching matrices (S2?-1 to S2?-AD).