Abstract: An apparatus for management of a spectral capacity of a wavelength division multiplexing, WDM, system includes at least one pair of transmission fibers provided for transporting optical signals. Each transmission fiber of a transmission fiber pair is connected to a first port of an optical circulator having at least two additional ports and adapted to transmit an incoming optical signal entering one of its ports via its next port. WDM subsystems configured with counter-propagating assignable wavelengths are connected to associated ports of the optical circulator of the apparatus.

Abstract: The invention relates to a method for migrating data traffic from an existing optical WDM transmission system to a new optical WDM transmission system, the existing optical WDM transmission system using a first optical transmission band and the new optical WDM transmission system being capable of using a second optical transmission band. The second optical transmission band at least partially includes the first optical transmission band and a further extension band that does not overlap with the first optical transmission band, the method including the steps of. According to the invention, a migration filter device is used in order to connect, during a migration phase, the network nodes of the existing system and the network nodes of the new system to the network paths that have been used by the existing system. During the migration phase, both systems are operated in parallel, with the new system using the extension band only.

Abstract: The invention relates to a method for migrating data traffic from an existing optical WDM transmission system to a new optical WDM transmission system, the existing optical WDM transmission system using a first optical transmission band and the new optical WDM transmission system being capable of using a second optical transmission band. The second optical transmission band at least partially includes the first optical transmission band and a further extension band that does not overlap with the first optical transmission band, the method including the steps of. According to the invention, a migration filter device is used in order to connect, during a migration phase, the network nodes of the existing system and the network nodes of the new system to the network paths that have been used by the existing system. During the migration phase, both systems are operated in parallel, with the new system using the extension band only.

Abstract: An apparatus for management of a spectral capacity of a wavelength division multiplexing, WDM, system includes at least one pair of transmission fibers provided for transporting optical signals. Each transmission fiber of a transmission fiber pair is connected to a first port of an optical circulator having at least two additional ports and adapted to transmit an incoming optical signal entering one of its ports via its next port. WDM subsystems configured with counter-propagating assignable wavelengths are connected to associated ports of the optical circulator of the apparatus.

Abstract: A method for engineering of a connection in a WDM photonic network with a plurality of flexibility sites connected by links comprises calculating a physical end-to-end route between a source node and a destination node and setting-up a communication path along this end-to-end route. An operational parameter of the communication path is continuously tested and compared with a test threshold. The path is declared established whenever the operational parameter is above the margin tolerance. The established path is continuously monitored by comparing the operational parameter with a maintenance threshold. A regenerator is switched into the path whenever the operational parameter is under the respective threshold, or another path is assigned to the respective connection. An adaptive channel power turn-on procedure provides for increasing gradually the power level of the transmitters in the path while measuring an error quantifier at the destination receiver until a preset error quantifier value is reached.

Abstract: A method for engineering of a connection in a WDM photonic network with a plurality of flexibility sites connected by links comprises calculating a physical end-to-end route between a source node and a destination node and setting-up a communication path along this end-to-end route. An operational parameter of the communication path is continuously tested and compared with a test threshold. The path is declared established whenever the operational parameter is above the margin tolerance. The established path is continuously monitored by comparing the operational parameter with a maintenance threshold. A regenerator is switched into the path whenever the operational parameter is under the respective threshold, or another path is assigned to the respective connection. An adaptive channel power turn-on procedure provides for increasing gradually the power level of the transmitters in the path while measuring an error quantifier at the destination receiver until a preset error quantifier value is reached.

Abstract: A method for engineering of a connection in a WDM photonic network with a plurality of flexibility sites connected by links comprises calculating a physical end-to-end route between a source node and a destination node and setting-up a communication path along this end-to-end route. An operational parameter of the communication path is continuously tested and compared with a test threshold. The path is declared established whenever the operational parameter is above the margin tolerance. The established path is continuously monitored by comparing the operational parameter with a maintenance threshold. A regenerator is switched into the path whenever the operational parameter is under the respective threshold, or another path is assigned to the respective connection. An adaptive channel power turn-on procedure provides for increasing gradually the power level of the transmitters in the path while measuring an error quantifier at the destination receiver until a preset error quantifier value is reached.

Abstract: An agile transparent network with a trail routing and switching (also called “engineering”) mechanism is provided that enables efficient use of regenerators and wavelengths available in the network, while maintaining a very efficient time-to-service. The trail engineering mechanism allows fast, automatic establishment of new connections based on the current network architecture, connectivity and loading and also on conditions in the connection request. Selection of regenerator sites and of the wavelengths used on each regenerator segment is performed with optimal use of current network resources, while ensuring that the quality of the selected trail is adequate for the respective call. The mechanism provides for both distance and performance balancing, and it optimizes the network response time.

Abstract: In the high-bit-rate transmission of optical signals in an optical transmission system having N optical fiber link sections with, in each case, one optical fiber and one dispersion compensation unit, the absolute-magnitude compensations of the first to Nth dispersion compensation units are dimensioned in such a way that the first to N?1-th fiber link sections is/are overcompensated, in each case, by approximately the same absolute magnitude overcompensation. Furthermore, the absolute-magnitude compensation of the Nth dispersion compensation unit is dimensioned in such a way that the accumulated fiber dispersion at the output of the optical transmission system is virtually completely compensated.

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 for determining signal quality in optical transmission systems, wherein the effective signal-to-noise ratio is determined by measuring amplitude histograms of a signal and by calculating characteristic histogram moments and additional interference is ascertained by comparing the characteristic histogram moments with the optical signal-to-noise ratio.

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 filter, adjustable add-drop-continue module and circuit for bundled cross-connect functionality, wherein the transmission response of the optical filter is varied by changing its temperature, tuning of the filter can be carried out by mechanical pressure or tension, the filter can be used to produce add-drop-continue modules which are suitable both for add-drop operation and for drop-continue operation, and cross-connect modules can be constructed from the optical filters.

Abstract: An agile transparent network with a trail routing and switching (also called “engineering”) mechanism is provided that enables efficient use of regenerators and wavelengths available in the network, while maintaining a very efficient time-to-service. The trail engineering mechanism allows fast, automatic establishment of new connections based on the current network architecture, connectivity and loading and also on conditions in the connection request. Selection of regenerator sites and of the wavelengths used on each regenerator segment is performed with optimal use of current network resources, while ensuring that the quality of the selected trail is adequate for the respective call. The mechanism provides for both distance and performance balancing, and it optimizes the network response time.

Abstract: A compensation system for adaptive equalization of an optical signal, wherein an optical filter, whose complex coefficients are adjustable, is used for signal equalization. The quality of the optical signal is used, after conversion to an electrical data signal, as a control criterion. The compensation device can largely compensate for distortion produced by dispersion, polarization mode dispersion or self phase modulation. An optical compensation filter with a wide free spectral range is used to compensate for the wavelength-dependent dispersion in a wavelength-division multiplexed system. The setting of the filter may be fixed, or may be adjusted adaptively in a closed control loop.

Abstract: A method and arrangement for the determination and separation of single channel effects “Group Velocity Dispersion” (GVD), “Self Phase Modulation” (SPM), “Intra Channel Cross-talk” (ICC) and “Stimulated Brillouin Scattering” (SBS) on optical transmission of a wavelength multiplex (WDM) signal which comprises several channels are disclosed. The channels are separated by a demultiplexer and fed to an electrooptical converter for the generation of electrical signals. The electrical signals comprising broadband frequency data contain distortions due to the single channel effects on optical transmission. The electrical signals are supplied to an electrical spectrum analyser and an electrical amplitude distributor for the analysis, determination and separation of the single channel effects.

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 for determining interactions between a number of optical channels in a wavelength division multiplexed signal wherein, given that during broadband optical transmission, the quality of a “Dense Wavelength Division Multiplexed” signal is adversely affected by multiple channel interactions, the method is used to determine the governing effects, the Kerr effect and the non-linear scattering process by evaluating the spectral profile of the Q factor or of the bit error rate.

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 agile network is provided with a layered control system for maintaining a network-wide target performance parameter (e.g. power) along all end-to-end connections. A connection is controlled at the physical layer using optical control loops that have a concatenated response based on a set of loop time constants. The network is separated into gain based span loops and power based switch loops; each link has a gain profile, and requires a per-wavelength power target as the output power target for the switch loop at the start of the link. Use of achievable gain for the span loops allow to optimize the performance of the link. Use of individual achievable power targets allows each switch loop to autonomously ramp on and off channels without causing interference with existing and other ramping channels. A loop control uses a model-based rules block, to distribute control signals to an optical section encompassing a plurality of optical components.