Abstract: A method for activating a card within a communication network, making it possible to minimize the power consumption cost of putting the card into effect. The method consists of seeking out, and activating as a priority, cards which are located in already-activated receptacles. A receptacle may be a tray or cabinet in a predetermined search range corresponding to one or more nodes of said communication network.

Abstract: A method for activating a card within a communication network, making it possible to minimize the power consumption cost of putting the card into effect. The method consists of seeking out, and activating as a priority, cards which are located in already-activated receptacles. A receptacle may be a tray or cabinet in a predetermined search range corresponding to one or more nodes of said communication network.

Abstract: Provided are a method for processing optical signals and a transmitter for the signals adapted for an ultra-high bit rate. The method uses an optical pulse stream with a carrier suppressed return to zero (CS-RZ) format to be obtained from an optical modulator that is driven using a combination of two sinusoidal electrical voltages, one at a frequency f and the other at the third harmonic 3f of the frequency f.

Abstract: A multichannel wavelength-division multiplex fiber optic transmission system includes an optical transmitter and an optical receiver connected by an optical line including at least one optical fiber and at least one set of channel regenerators. Successive regenerators regenerate respective groups of channels forming a subset of the set of channels.

Abstract: The invention is also related to devices for a synchronization of data in an optical WDM transmission system, consisting of the following parts: A wavelength demultiplexer (1) for demultiplexing the incoming data stream in the synchronizer, delay lines (2) for the individual wavelength channels, a multiplexer (10), a modulator (3) modulated by a high frequency clock signal (5) and at least one photodetector (4) tapped to output line (B) where the photodetector (4) is connected to an electronic control circuit (6) which is connected to the findividual delay lines (2) for an automatic delay control.

Abstract: The present invention propose to use an optical multiplexer associated with an optical clock as a wavelength converter. Each RZ coded tributary will be carried by a single wavelength (channel) passively interleaved with the others without interferometric interaction hence achieving a not necessarily perfect OTDM. This input data stream as optical data signal composed of different wavelengths is then launched on at least one data access of said optical multiplexer used as a wavelength converter. An optical clock at the desired bit-rate is launched on the probe access of said optical multiplexer synchronously to the multi-wavelength data stream. At the output, the initial clock wavelength is converted on data signal using the gain conversion property of the optical multiplexer. In such a way, a data stream of substantially higher bit-rate is obtained while due to a very precise synchronization a lost of data is minimized.

Abstract: It is an object of the present invention to provide a method for processing optical signals and a transmitter for the signals adapted for ultra-high bit rate without implying obligatory a substantial increase in costs. This object is achieved by applying a method for processing optical signals to be transmitted through an optical transmission line using optical pulse stream with a carrier suppressed return to zero (CS-RZ) format to be obtained from at least an optical modulator. That method is characterized by driving the optical modulator with a combination of two sinusoidal electrical voltages, one at some frequency f and the second one at the third harmonic 3 f of such frequency.

Abstract: The invention is related to a synchronizer for more than one optical RZ signal in a wavelength multiplex transmission system comprising at least one variable delay line (1) with an input receiving RZ-WDM optical channels (2), at least one delay controller (3) receiving the RZ-WDM output optical channels (10), the delay controller generating a control signal depending on the power of the RZ-WDM output optical channels (10) and a control circuit (9) to control the at least one delay line (1) in such a way that the optical WDM channels are synchronized.

Abstract: The present invention provides a generator of a CS-RZ optical clock signal at a predetermined clock frequency. The generator contains a first laser source and a second laser source which respectively produce first and second continuous lightwaves, where the laser frequency of at least one of the sources is adjustable. The generator also contains a coupler disposed to receive the first and second lightwaves and forms optical beats at a beat frequency. An opto-electronic feedback is used to servo-control the adjustable-frequency laser source(s) in such a manner that the beat frequency, which is equal to the difference between the laser frequencies, is substantially equal to the clock frequency.

Abstract: The invention relates to a device for regenerating optical signals by intensity modulation and phase modulation of the optical signals, said device including: a mode locking laser for recovering a clock signal representing the clock of the bits of the optical signals to be regenerated, and a modulation interferometer structure having a first interferometer arm and a second interferometer arm, enabling amplitude modulation and phase modulation of optical signals by said clock signal, and including a semiconductor amplifier in the first interferometer arm. The mode locking laser is coupled to said first interferometer arm so that said amplifier of the first interferometer arm is a common component of the mode locking laser and said interferometer structure.

Abstract: To delay optical signals precisely and continuously in a very small dynamic range, a device for applying a time-delay to optical signals includes a first phase modulator to receive an input optical signal carried by an original center wavelength and to apply a first stage of phase modulation to the carrier wave of the input signal to supply a first intermediate signal carried by a modified center wavelength, a delaying dispersive member having chromatic dispersion to receive the first intermediate signal and to supply a second intermediate signal, and a second phase modulator to receive the second intermediate signal and to apply a second stage of phase modulation to the carrier wave of the second intermediate signal to supply an output signal carried by the original center wavelength. Applications include optical telecommunication systems, in particular converting wavelength division multiplexed signals into time division multiplexed signals and regenerating wavelength division multiplexed signals.

Abstract: Known optical power equalizers receive an optical main input signal modulating between high and low input power levels. The optical power equalizers emit an equalized optical main output signal modulating between high and low output power levels, where at least one of the two sets of high and low power levels is equalized to one high or one low output power level. Such devices can comprise at least one gain-clamped semiconductor optical amplifier that operates about its saturation range. The optical power equalizer receives an amplifier input signal, which has one or more modulated portions, and emits a modulated amplifier output signal. According to the invention the dependence of the gain-clamped semiconductor optical amplifier's gain on the power of the amplifier input signal is adjusted such that the high input power levels of the amplifier input signal are equalized into the one high output power level of the amplifier output signal.

Abstract: An optical module advantageously uses optical conversion fibers not only for a single channel but for sets of channels that are, in a specific way, selected from a multi-channel wave division multiplex (WDM) grid. The sets of channels are defined such that four wave mixing is negligible or has a negligible effect. The optical module has a demultiplexer, a multiplexer, and parallel optical conversion fiber portions that are arranged between the demultiplexer and the multiplexer. Each of the parallel optical conversion fiber portions has a specific dispersion map and transmits a different set of channels of the multi-channel WDM grid. These channels are regularly spaced from each other.

Abstract: The invention provides a generator of a CS-RZ optical clock signal at a predetermined clock frequency, the generator comprising:

Abstract: The present invention is based on the advantageous use of optical conversion fibers not only for a single channel but for sets of channels chosen in a precise way out of the used multi-channel WDM grid. The sets of channels are defined such that four wave mixing are or negligible or of a negligible effect.

Abstract: The present invention propose to use an optical multiplexer associated with an optical clock as a wavelength converter. Each RZ coded tributary will be carried by a single wavelength (channel) passively interleaved with the others without interferometric interaction hence achieving a not necessarily perfect OTDM. This input data stream as optical data signal composed of different wavelengths is then launched on at least one data access of said optical multiplexer used as a wavelength converter. An optical clock at the desired bit-rate is launched on the probe access of said optical multiplexer synchronously to the multi-wavelength data stream. At the output, the initial clock wavelength is converted on data signal using the gain conversion property of the optical multiplexer. In such a way, a data stream of substantially higher bit-rate is obtained while due to a very precise synchronization a lost of data is minimized.

Abstract: The invention is also related to a devices for a synchronization of data in an optical WDM transmission system, consisting of the following parts: A wavelength demultiplexer (1) for demultiplexing the incoming data stream in the synchronizer, delay lines (2) for the individual wavelength channels, a multiplexer (10), a modulator (3) modulated by a high frequency clock signal (5) and at least one photodetector (4) tapped to output line (B) where the photodetector (4) is connected to an electronic control circuit (6) which is connected to the individual delay lines (2) for an automatically adaptation.

Abstract: To resynchronize input optical signals with different optical carrier frequencies f1, f2 a delayed optical signal is created by applying a variable time-delay to one of the signals. A combination signal is formed by coupling measurement optical signals respectively obtained from the delayed signal and from the other input signal. A mixed signal is formed by injecting the combination signal into a non-linear optical device. A filtered signal is formed from the mixed signal using a filter tuned to an optical frequency f3 equal to p.f1+q.f2, p and q being relative integers such that the frequency f3 is different to the frequencies f1 and f2 of the carrier waves. The variable time-delay is controlled in accordance with a control electrical signal representative of the average value of the intensity of the filtered signal. Applications include wavelength-division multiplex optical communication systems.

Abstract: The invention refers to an optical power equalizer. Known devices receive an optical main input signal modulating between high and low input power levels. They emit an equalized optical main output signal modulating between high and low output power levels, where at least one of the two sets of high and low power levels is equalized to one high or one low output power level. Such devices can comprise at least one gain-clamped semiconductor optical amplifier, adjusted to work about its saturation range, receiving an amplifier input signal, consisting of one or more portions of which at least one is modulated and emitting a modulated amplifier output signal. According to the invention the dependence of the GC-SOA's gain on the power of the amplifier input signal is adjusted in such a way, that the high input power levels of said amplifier input signal are directly converted into the one high output power level of said amplifier output signal.

Abstract: The invention relates to an optical fiber transmission system using soliton signals with wavelength division multiplexing in which the wavelengths, &lgr;1 to &lgr;n, of the various channels of the multiplex are selected in such a manner that at least one point of the transmission system, the difference between the bit times of any two channels of the multiplex is substantially a submultiple T/N of the clock period. The invention proposes placing a synchronous modulator at said point to modulate the soliton signals at a frequency N/T which is a multiple of the soliton clock frequency 1/T. In a frequency allocation scheme that ensures that the bit times of the channels are synchronous at an interval ZR, this makes it possible to modulate all of the channels at intervals that are submultiples of ZR by using modulation frequencies that are multiples of the clock frequency.