Abstract: A Raman module comprises a detecting unit for measuring the output power of a WDM signal traveling along a fiber section, and a spectral gain estimating unit for determining an estimated vector gain Gainmeas based on the output power alone. The Raman pump signal is controlled with a gain GainRA evaluated based on the estimated gain Gainmeas so that all channels have a similar gain. The spectral gain estimating unit comprises a fiber gain model and an input signal adjust unit. The model receives the output power, assumes a predicted input power for each channel and provides a corresponding estimated output power for each channel. The input signal adjust unit adjusts the predicted input power based on an error signal provided by the model. The gain is then calculated from the predicted input powers and the estimated output powers. The detecting unit demultiplexes a fraction of the WDM signal into n sub-band and detects sub-band optical power PB1, . . . PBn.

Abstract: The invention relates to a modular optical network node, which divides the optical input signals into optical subbands, processed by a central element or by several central elements and which then recombines the optical subbands once again to form an optical output signal. Various functionalities, such as add-drop functionality, a drop and continue functionality, a multicast functionality, a broadcast functionality, a ring interconnect functionality, and a cross connect functionality, can be assigned to the central element or to the central elements of the modular optical network node. According to the assignment of a functionality, the modular optical network node can be used in networks having a different structure.

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 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 said end-to-end route. An operational parameter of said communication path is continuously tested and compared with a test threshold. The path is declared established whenever the operational parameter is above said margin tolerance. The established communication 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.

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: 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 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 nonlinear scattering process by evaluating the spectral profile of the Q factor or of the bit error rate.