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 method for measuring the signal quality of an optical data signal is provided. To measure the signal quality, and in particular the signal-to-noise ratio of an optical data signal which has data-free time intervals, the signal strength of the transmitted optical data signal is measured during a data transmission. The signal strength of the noise signal is determined during the data-free time intervals. The signal-to-noise ratio is determined and used as a criterion for the signal quality of the optical 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: 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: The invention relates to a measuring method that allows to measure non-linearities of an optical fiber (OF) unilaterally, that is at the beginning or at the end of the optical fiber (OF). To this end, an optical test signal (ots) is launched into the optical fiber (OF), the test signal power (Ps) of which is modified. A first entry threshold (SBS1) of the stimulated Brillouin scattering is detected on the basis of the modified power (Pros) of the reflected optical signal (ros). In a second step, at least one modulated optical pump signal (ops) is launched into the optical fiber (OF) in addition to the optical test signal (ots). A second entry threshold (SBS2) of the stimulated Brillouin scattering is detected on the basis of the modified power (Ps) of the optical test signal (ots). The non-linearity coefficient (&ggr;) of the optical fiber (OF) is determined by evaluating the at least first and second entry thresholds (SBS1, SBS2), the test and pump signal parameters and the fiber parameters.

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: The invention relates to a method and to a system for amplitude modulation of an optical signal (os) with a binary data signal (ds). To this end, the optical signal (os) is divided up into a first and a second adjustable optical signal (os1, os2). The first optical signal (os1) is supplied to a modulator (MZM) that outputs an optical transmission signal (ts) after amplitude modulation with a binary data signal (ds). A counter-phase second optical signal (gps) is produced from the second adjustable optical signal (os2) and the optical transmission signal (ts) and the counter-phase second optical signal (gps) are combined to a carrier-reduced optical transmission signal (rts).

Abstract: The stimulated Brillouin backscatter is reduced by non-linear effects, such as self-phase modulation or cross-phase modulation. Due to the cross-phase modulation, a bandwidth spread and, as result thereof, a reduction of the stimulated Brillouin backscatter is also achieved by supplying at least one amplitude-modulated pump signal.

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: 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: Method for phase-synchronous supply of an optical pulsed signal or an optical NRZ transmission signal and an electrical data signal, wherein an optical pulsed signal and an electrical data signal which are synchronized with respect to an electrical clock signal are supplied to an electrooptical modulator in order to produce an optical RZ transmission signal. In order to control the phase-synchronous supply, a portion of the optical RZ transmission signal is output, and the output portion is converted to an electrical signal. The power, the current or the voltage of the electrical signal is then determined in a narrow frequency band around the frequency which corresponds to half the data rate, and the determined power, current or voltage values are used to control the phase-synchronous supply of the optical pulsed signal and/or of the electrical data signal.

Abstract: A method and apparatus for improving the signal quality of a modulated optical transmission signal wherein at least one optical signal whose frequency is reduced from the carrier signal frequency by the Brillouin frequency shift is produced in a signal production unit and this signal is injected at the end of the optical transmission fiber in the opposite direction to the transmission signal direction, so that the carrier signal component of the modulated optical transmission signal is reduced.

Abstract: When merging optical pulse streams having a high bit rate, there is the problem that, for example given a bit rate of 40 Gbit/s, the pulses at the multiplexer output have 25 pulses temporal spacing and approximately 5 mm spatial spacing. Given a precision of 10% of the bit rate, the light waveguides must be matched with a precision of 0.5 mm, which previously required mechanical or inserted length-adjustable open beam optics and which leads to high outlay. In the optical delay line, by contrast, the temperature of a light waveguide is varied such that the desired optical length is set via the change in the refractive index of the optical fibers. The optical fibers are wound on coil bodies that have a through bore containing a heating element connected to a temperature control.

Abstract: For the purpose of electric compensation of signal distortion in an optical telecommunication system caused by laser chirp and fiber dispersion, a correction signal is derived from the electric transmission and/or reception signal by squaring followed by differentiation and added to the electric transmission signal and/or reception signal, respectively, after necessary attenuation.