Abstract: An anti-pump laser (AL) is used in addition to a tilt correction pumplaser (KL) for Raman tilt control, said anti-pump laser injecting an anti-pump signal into a transmission fiber (FI) or a dispersion compensation fiber (DCF). The anti-pump laser (AL) has the function of reducing the pump energy of the control pump laser (KL) in the course of the fiber (FI, DCF), in order to restrict its effective length and to enable a faster adjustment of the tilt.

Abstract: Methods are described for preemphasizing an optical multiplex signal that comprises a plurality of signals having different wavelengths, which are transmitted by a transmitter to a receiver. Power levels for the signals are set at the transmitter and measured at the receiver. A mean power level for the transmit-side signals is ascertained. New signal power level values are ascertained from the current power levels of the signals at the transmitter and at the receiver and set on the transmit side such that signal-to-noise ratios for all signal are approximately equalized at the receiver. In order to make more precise settings for the preemphasis, mean gain values and mean attenuations are ascertained from the sum power levels for the multiplex signal measured at the input and at the output of each amplification section and incorporated together with an effective noise figure into the process of ascertaining the new signal power level values.

Abstract: The invention relates to a method and a system for controlling a PMD compensator (2). For this purpose, a measuring signal (MS) is branched off from an already compensated optical data signal (ODSK) and supplied to a polarization adjuster (2). The output signal of the latter is supplied to an optical filter unit (61) and subdivided into two optical measuring signal components (OMKI, OMK2) having different polarizations. After a respective opto-electrical conversion, the spectra are compared with each other in an analysis and control unit (81) and the PMD compensator (2) is adjusted in such a manner that they are as identical as possible.

Abstract: Binary signals are converted at the transmission end into two optical signals which are combined into a polarization multiplex signal and are then transmitted. The transmitted polarization multiplex signal is divided at the receiving end into two polarized signal parts which are converted in a linear manner into orthogonal electrical components and are supplied to a multidimensional filter. Said multidimensional filter replaces a polarization controller, restores the signal values that correspond to the signals at the transmission end, and compensates signal distortions.

Abstract: A transmitter-side transmission signal for compensating disturbances caused by e transmission properties of an optical transmission system is provided. A high-bit-rate-binary signal is serially introduced into an N-level-shift register. A bit pattern whose bit number depends on the transmission system disturbance influence is removed from the shift register and introduced into comparators connected to comparative-value registers. The comparative-value registers include values received from a transmission function and from various binary-bit patterns. In the comparators, the binary-bit pattern introduced is converted into a binary combination which is introduced into a digital-analog transducer, which transmits a compensation signal, corresponding to a discrete value for the amplitude or phase of the transmission signal corresponding a desired signal form, to a modulator.

Abstract: In order to synchronize the phases of two RZ data signals (RZS1, RZS2) combined to form a time multiplex signal (MS1), the power of half the fundamental made of the multiplex signal (MS1) is measured and the phase difference is controlled such that its power assumes a minimum.

Abstract: In one aspect, a WDM signal is assigned to a number of sub-bands with the channel spacing being correspondingly enlarged in each sub-band. The spectral hole burning is hereby essentially reduced, since this effect is restricted to the adjacent channels. The complete WDM signal is first pre-amplified before being divided into sub-bands.

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: An apparatus is provided for compensating for polarization mode dispersion which is caused during transmission of a light wave via an optical waveguide, to an optical communication network having such an apparatus, and a method for compensating for polarization mode dispersion which is caused during transmission of a light wave via an optical waveguide is also provided.

Abstract: A method of splitting an optical data signal starting with an optical data signal split into n equal data sub-signals, and an optical binary auxiliary signal with the same bit rate and phase is added to each optical data sub-signal. Each nth bit of the optical binary auxiliary has a higher level, with the phases of each of the n optical auxiliary signals showing a relative displacement of one bit. As a result, n aggregate signals are generated, each of which is fed to a decision-maker. A decision-maker threshold is set above the amplitude of the data sub-signal and below the amplitude of the aggregate signal. Each decision-maker, therefore, emits an electrical data signal with 1/n times the bit rate of the data signal.

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: Pump energy with a wavelength which is below the wavelength of an optical signal is fed into a transmission section from a pump laser via a coupler. The received optical signal is attenuated with increasing pump power with signals having higher frequencies being more strongly damped.

Abstract: The invention relates to a method and an arrangement for determining the dispersion of an optical transmission link. By determining the signal quality, the bit error rate is measured for a modulated data signal depending on the modulation frequency of a noise signal (STS). The dispersion coefficient of the transmission link is calculated on the basis of the resulting discrete minima of the bit error rates. These measurements can take place advantageously during the operation of the data transmission. The method also provides additional information about the quality of the data transmission by determining the non-linear phase shift.

Abstract: Methods are described for preemphasizing an optical multiplex signal that comprises a plurality of signals having different wavelengths, which are transmitted by a transmitter to a receiver. Power levels for the signals are set at the transmitter and measured at the receiver. A mean power level for the transmit-side signals is ascertained. New signal power level values are ascertained from the current power levels of the signals at the transmitter and at the receiver and set on the transmit side such that signal-to-noise ratios for all signal are approximately equalized at the receiver. In order to make more precise settings for the preemphasis, mean gain values and mean attenuations are ascertained from the sum power levels for the multiplex signal measured at the input and at the output of each amplification section and incorporated together with an effective noise figure into the process of ascertaining the new signal power level values.

Abstract: An anti-pump laser (AL) is used in addition to a tilt correction pumplaser (KL) for Raman tilt control, said anti-pump laser injecting an anti-pump signal into a transmission fiber (FI) or a dispersion compensation fiber (DCF). The anti-pump laser (AL) has the function of reducing the pump energy of the control pump laser (KL) in the course of the fiber (FI, DCF), in order to restrict its effective length and to enable a Faster adjustment of the tilt.

Abstract: Binary signals are converted at the transmission end into two optical signals which are combined into a polarization multiplex signal and are then transmitted. The transmitted polarization multiplex signal is divided at the receiving end into two polarized signal parts which are converted in a linear manner into orthogonal electrical components and are supplied to a multidimensional filter. Said multidimensional filter replaces a polarization controller, restores the signal values that correspond to the signals at the transmission end, and compensates signal distortions.

Abstract: Method for reducing signal degradation in an optical polarisation-multiplex system. The modulated optical signals to be transmitted are synchronised or generated such that the phase difference for NRZ-modulated signals is at least approximately 0° and the phase difference for RZ-modulated signals is at least approximately 180°. They can also be achieved by means of different synchronising devices.

Abstract: At the transmitter end, route information is converted to allocated frequency mixes that are used to produce route signals by modulating a carrier signal. The route signals produced are placed in front of and/or after at least one data packet and are transmitted within an optical data packet stream. At the receiver end, the route information is evaluated in terms of the frequency mix used for the modulation and the data packets are switched using the route information obtained from the frequency mixes.

Abstract: A method and system for optimization of an optical transmissions signal which is modulated with a binary data signal, wherein a control device ensures that the operating point and the modulation signal of a Mach-Zehnder modulator are set optimally, with the fundamental frequency and/or the first harmonic frequency of the transmission signal being selected for this purpose, and an optimum setting is reached when the amplitude of the fundamental frequency has reached a maximum value and the amplitude of the harmonic frequency has reached a minimum value.

Abstract: A measurement method is provided for determining nonlinearities in an optical fiber wherein, in a first step, at least one optical test signal is injected into the optical fiber, whose test signal power is varied, and a first onset threshold for the stimulated Brillouin scatter is determined on the basis of the change in power of the back scattered optical signal and, in a second step, in addition to the optical test signal, at least one modulated optical pump signal is injected with a predetermined pump signal power and at a first pump wavelength into the optical fiber, and a second onset threshold for the stimulated Brillouin scatter is determined on the basis of the change in the test signal power, and the nonlinearity coefficient of the optical fiber is determined by evaluating at least the first and the second onset threshold, the test and pump signal parameters and the fiber parameters.