Abstract: A receiver for optical signals is described, comprising a Viterbi equalizer which comprises an analog electronic equalizer as a filter for the signals before the signals are to be processed by the Viterbi equalizer, and a receiver for optical signals is described, comprising a Viterbi equalizer which comprises a parameter-estimation device for obtaining estimated values indicating the degree of distortion of the optical signal connected with the analog signal path, with the parameter-estimation device connected with the Viterbi equalizer for transmitting the estimated values gained from the analog signal to the Viterbi equalizer, plus a method is described for improving an optical receiver's ability to identify digitalized data transmitted by analog optical signals, comprising the steps of analog filtering of the analog signal, subsequent analog-to-digital conversion of the analog signal into a digital soft-data signal, feeding the digital soft data to a Viterbi equalizer, relating the digital soft data to bi

Abstract: An optical receiver has an adaptive optical compensator and/or an adaptive electrical equalizer for compensating signal distortion in a received optical signal. In order to achieve a very fast adaptation of the receiver to the actual signal distortion, which is important for example for bursts mode optical signals in a packet-switched optical transmission network, at least one predetermined trainings sequence is provided in the optical signal, which is known at the receiver and thus enables fast adaptation of the compensator and/or equalizer to the actual signal distortion.

Abstract: An integrated chromatic dispersion compensator for optical signals in optical communication networks, comprising a plurality of cascaded stages of optical dispersion elements arranged in the form of a lattice filter structure, is characterized by at least one tapping device disposed between consecutive stages of the optical dispersion elements for tapping inter stage signals, feeding each tapped inter stage signal into a separate feedback loop, which in turn is feeding adaptation parameters into at least one of the stages of the optical dispersion elements preceding the corresponding tapping device of the inter stage signal. The invention presents a compact dispersion compensator that can dynamically be adapted to varying dispersion situations and that is capable of compensating the chromatic dispersion of a multitude of data channels at the same time.

Abstract: The present invention provides an optical waveguide phase shifter that comprises a planar silicon-dioxide-containing optical glass waveguide whose core contains glass, and also a planar optical polymer waveguide whose core contains a polymer and/or a mixture of polymers, furthermore means that effect the change in the temperature of the planar optical polymer waveguide and wherein the refractive index of the planar optical polymer waveguide is greater than the refractive index of the planar silicon-dioxide-containing optical waveguide. The refractive indices of the planar optical polymer waveguide and of the silicon-dioxide-containing optical glass waveguide can consequently be matched even by a small increase in the temperature of the planar optical polymer waveguide. In addition, only the propagation constant of the optical field in a silicon-dioxide-containing optical waveguide according to the invention is influenced by the coupling mode between silicon-dioxide waveguide and polymer waveguide.

Abstract: A variable optical delay line that has a first input (16), a first output (36), and a first phase shifter stage (10) including a first phase-shifting element (41). A first delay stage (12) is connected to the first phase shifter stage (10) and has a second phase-shifting element (44). A second phase shifter stage (14) is connected to the first delay stage (12) and has a third phase-shifting element (46). The first phase shifter stage (10), the first delay stage (12) and the second phase shifter stage (14) form a Mach-Zehnder structure, and the first, the second and the third phase-shifting elements (41, 44, 46) are driven in such a way that the variable optical delay line (100) generates a predetermined delay.

Abstract: An integrated chromatic dispersion compensator for optical signals in optical communication networks, comprising a plurality of cascaded stages of optical dispersion elements arranged in the form of a lattice filter structure, is characterized by at least one tapping device disposed between consecutive stages of the optical dispersion elements for tapping inter stage signals, feeding each tapped inter stage signal into a separate feedback loop, which in turn is feeding adaptation parameters into at least one of the stages of the optical dispersion elements preceding the corresponding tapping device of the inter stage signal. The invention presents a compact dispersion compensator that can dynamically be adapted to varying dispersion situations and that is capable of compensating the chromatic dispersion of a multitude of data channels at the same time.

Abstract: A polarization mode dispersion (PMD) controller device for controlling the state of polarization of an optical light wave comprising a dispersion compensation unit (2; 25; 40) and an adaptation control unit (6; 28; 44), wherein the dispersion compensation unit (2; 25; 40) comprises a multitude of compensation stages processing the optical light wave, and wherein the adaptation control unit (6; 28; 44) controls the dispersion compensation unit (2; 25; 40) is characterized in that at least one feed-forward signal tap (4; 26a-26c, 73a-73c) is provided tapping the optical light wave inserted into one of the compensation stages, that the feed-forward signal(s) is(are) fed into a distortion analyzer unit (5; 27; 66) and that the distortion analyzer unit (5; 27; 66) provides the adaptation control unit (6; 28; 44) with information about the incoming optical light wave. It accelerates the adaptation speed and lowers the costs of a high-speed PMD controller device.

Abstract: A digital signal processing (=DSP) receiver for analyzing an optical signal, in particular in a terabit optical network, comprising a receiver input (11; 21; 31) for receiving the optical signal, a photo diode (15a, 15b; 26a, 26b; 36a, 36b), an analog-to-digital conversion (=ADC) unit (16a, 16b; 27a, 27b; 37a, 37b), and a DSP processing unit (17; 28; 38), is characterized in that the DSP receiver comprises a splitting unit (12; 22; 33) splitting the optical signal and feeding the split parts into at least two waveguide branches (13a, 13b; 23a, 23b; 34a, 34b), that at least one waveguide branch comprises an optical filtering element (14a, 14b; 24a, 24b, 25a, 25b; 35a, 35b), that each waveguide branch is fed onto a separate photo diode (15a, 15b; 26a, 26b; 36a, 36b), that the signal of each photo diode is fed into a separate ADC unit (16a, 16b; 27a, 27b; 37a, 37b), and that the signal of each ADC unit is fed into the DSP processing unit (17; 28; 38).

Abstract: An amplifier system for satellites, in particulars for radio-frequency amplifier systems incorporating travelling wave tube amplifiers and used in space repeaters. The amplifier system includes two amplifier modules, a signal divider, and a signal combiner. A first output of the divider is connected to an input of the first amplifier module via a connection length Le1. A second output of the divider is connected to input of the second amplifier module via a connection length Le2. An output of the first amplifier module is connected to a first input of the combiner via a connection length Ls1. An output of the second amplifier module is connected to a second input of the combiner via a connection length Ls2. The connection lengths satisfy the equation Le1+Ls1=Le2+Ls2 and the connection length Ls1 is different from the connection length Ls2.

Abstract: An inclusion of the liquid crystal in the direct vicinity of the core of an optical waveguide structured on a substrate allows to build a tunable optical device. The liquid crystal will be confined by replacing cladding material of that integrated structure. The tuning of the property of that liquid crystal i.e. its refractive index will influence directly the mode index of the core. This influence can be of such amount to allow to control the flow of optical signals transmitted through it. The tuning is advantageously achieved by applying some electric field via electrode on a segment of that core confined with liquid crystals.

Abstract: An optical time multiplexer for generating an N Gbits/s output signal (36) from n data modulated input pulse streams (21, 22) with a pulse frequency of N/n GHz, where n∈IN and n≧2, with a combiner device for passively interleaving the n input pulse streams (21, 22) is characterized by at least n−1 first phase shifting elements (25) tuning the optical phases of at least n−1 input pulse streams (22) and being connected to a controller device (32), which derives at least n−1 control signals from a comparison of the optical phases of the n input pulse streams (21, 22) and controls the at least n−1 first phase shifting elements (25) such that the optical phases of all n input pulse streams (21, 22) are locked with respect to each other.

Abstract: The invention relates to a wavelength division multiplex transmission (WDM) system or a polarisation division multiplex division system with an optical transmitter (OT), an optical receiver (OR) and an optical transmission fiber (TF), the receiver (OR) showing means for measuring dispersion characteristics while transmitting optical signals over the transmission fiber (TF), the transmitter (OT) comprising means for sending correlation signals (CP) on at least two different wavelength or polarisation channels and the receiver (OT) comprising means for performing a correlation determination

Abstract: The invention concerns a high speed optical transmitter, comprising at least one optical time division multiplexer, that is designed to generate a multiplexed signal with return-to-zero like pulse form out of at least two input signals, wherein further a conversion filter at the output of the optical transmitter is comprised and wherein the conversion filter shows filter means for generating an optical output signal with broadened pulses for reducing the use of spectral bandwidth, as well as an optical transmission system and a method therefore.

Abstract: The present invention provides an optical waveguide phase shifter that comprises a planar silicon-dioxide-containing optical glass waveguide whose core contains glass, and also a planar optical polymer waveguide whose core contains a polymer and/or a mixture of polymers, furthermore means that effect the change in the temperature of the planar optical polymer waveguide and wherein the refractive index of the planar optical polymer waveguide is greater than the refractive index of the planar silicon-dioxide-containing optical waveguide. The refractive indices of the planar optical polymer waveguide and of the silicon-dioxide-containing optical glass waveguide can consequently be matched even by a small increase in the temperature of the planar optical polymer waveguide. In addition, only the propagation constant of the optical field in a silicon-dioxide-containing optical waveguide according to the invention is influenced by the coupling mode between silicon-dioxide waveguide and polymer waveguide.

Abstract: The invention relates to a variable optical delay line that has a first input (16) and a first output (36) having a first phase shifter stage (10) comprising a first phase-shifting element (41).

Abstract: A device for adjusting the polarization of an incoming optical signal with a polarization divider (1), a first phase setter (3) in the signal path of at least one of the two output signals from the polarization divider, a first optical coupler (4), a second phase setter (5) in the signal path of at least one of the two output signals from the first optical coupler, and with a second optical coupler (6), an actuating signal being supplied to the phase setters respectively in a feedback loop, said actuating signal being obtained from a quality signal derived from the processed optical signal, is characterized in that a substraction element (10) is provided, to which the two parallel optical signals are supplied from a point after the first optical coupler, a bipolar quality signal being obtained in the substraction element from the difference of the two signals supplied, and that a control element (11) is connected downstream of the substraction element, which control element generates an actuating signal to on

Abstract: An arrangement and a method are disclosed for compensating for distortion in an optical signal having data modulated thereon which was caused by distortion effects on an optical fiber link, using a dispersion compensator which processes the incoming optical signal such that an optical or electric signal having the data of the input signal modulated thereon is provided at its output, with the output signal of the dispersion compensator exhibiting a distortion reduced from that of the input signal. The arrangement and the method are characterized in that the dispersion compensator is preceded by an optical bandpass filter which limits the spectral range of the incoming optical signal to a narrower range. In this way, even optical signal distortion due to higher-order dispersion effects can be selectively compensated for with simple technical means such that greater link lengths and more reliable adaptation to varying transmission conditions become possible.

Abstract: A process is proposed for recovering disturbed digital signals, wherein the electrical signals pass through a feedback equalizer and an analogue control of the setting parameters of the equalizers is performed. A pseudo-error monitor, which facilitates a high-speed adjustment of decision element thresholds, is also provided.

Abstract: A method for measuring interference effects on a glass fiber transmission link produced by polarization mode dispersion, whereby an optical light source feeds a side band modulated signal into the transmission link, the signal is transmitted and at a coherent receiver the signal is evaluated at a frequency corresponding to the modulation frequency of the side band modulated signal.

Abstract: A method and a regenerative filter for equalizing an input digital signal is proposed, wherein the received input signals is processed by means of threshold decision elements, multiplexers, and a delay unit 6, which regenerates a delayed signal for switching the multiplexer, wherein the input signal 1 passes in parallel through at least 4 threshold decision elements 2 and the output signals 3 of the threshold decision elements 2 are connected by at least one multiplexer 4 to the delay unit 6 and the delay unit 6 is comprised of at least two delay stages, whose delayed signals 9, 10 switch the at least one multiplexer 4.