Abstract: The invention relates to a communications backbone interface between at least three members of a communications network for a space vehicle. In the invention, the interface combines various signals received at inlets, which signals may be analog, digital, and optical, coming from two members, and produces a multiplexed optical signal for delivery to a member of the vehicle, such as a piece of equipment. The invention also provides to a communications terminal interface, a communications network having such interfaces, and an optical fiber harness.

Abstract: The invention relates to a system for conveying digital signals inside a space vehicle between a transmitter and a receiver. In the invention, the link between the transmitter and the receiver comprises a first portion made of optical fiber and a second portion in which infrared radiation propagates without guidance. A particular application lies in conveying remote control and telemetry signals within a satellite between a control module and a piece of equipment.

Abstract: The system includes processors each of which can drop an optical signal contained in one channel of an incoming optical multiplex signal and add an optical signal to the multiplex signal channel thereby made available. Each processor includes an optical signal drop filter and an optical signal add filter for an individual channel of particular wavelength, and these filters are connected by an optical switch. The drop filters and the add filters of the circuits of the system are connected in series, some in a drop subsystem and the others in an add subsystem, to transmit the multiplex signal from one filter to the other and from the drop subsystem to the add subsystem. They are distributed in order of decreasing drop or add wavelength from the input of the system at which the incoming multiplex signal is received.

Abstract: A switch which avoids imparting interference noise, limiting communications speed, and imparting losses, includes n passive couplers, each of which is provided with a number k of outlets, and with an inlet suitable for receiving one input signal; and k wavelength multiplexers, each of which is provided with n inlets set to respective ones of n wavelengths. For each multiplexer, that one of its inlets which is set to one of the wavelengths, is coupled via an amplifying optical gate to one of the outlets of that one of the couplers that is organized to receive an input signal carried by the same wavelength. The switch is used in performing routing functions in communications networks having optical links.

Abstract: The matrix comprises: a first stage having r switch modules each having 2p2 inlets and 2p.r outlets; and a second stage comprising r switch modules each having 2p.r inlets and 2p2 outlets. The outlets of the first stage are connected to inlets of the second stage via links which are mutually parallel in groups of 2p links, thereby reducing the number of crossover points, and thus reducing size. If the matrix is implemented using photonic technology, these links are implemented by means of optical fiber ribbons. The invention is applicable to photonic switch networks.

Abstract: An amplifier unit for a wavelength-division multiplex transmission system is proposed that has a first optical amplifier, a second optical amplifier and a connection present between the amplifiers. The amplifier unit contains a fiber section made of a dispersion-compensating fiber, said dispersion-compensating fiber being pumped by at least one pump light source and being used as Raman amplifier. The optical amplification of the dispersion-compensating fiber overcompensates for the loss in the connection between the amplifiers.

Abstract: In packet time-division multiplexing communications systems using optical networks, an optical method and circuits used in electrical-to-optical conversion interfaces assure that data rates of the electrical domain match the data rates of the optical domain. An optical method of concatenating binary information contained in successive time windows of an input signal includes forming g converted input signals obtained by amplitude modulating g optical carrier waves having different wavelengths, each converted input signal presenting, within the time windows, amplitude modulation as a function of the input signal. The method also includes forming a multiplex signal made up of a combination of g delayed signals obtained by applying delays to the converted input signals, the delays being such that any two consecutive delayed signals are offset in time by the duration w of the time windows.

Abstract: The invention is related to a wavelength allocation scheme for a WDM (Wavelength Division Multiplex) equipment with a distribution of used optical channels that are arranged around a saturation channel in a way that the total spectrum of the optical channels is balanced independent from the number of equipped optical channels.

Abstract: The matrix comprises:

Abstract: A protected optical switch matrix having N inputs and N outputs and including an optical switching fabric (S2-S2′), an input interface (S1) performing wavelength conversion and an output interface (S3) performing wavelength filtering. The input interface (S1) and the output interface (S3) are protected by redundancy provided by r redundant units for E working units where r is a number very much less than E.

Abstract: A protected optical switch matrix having N inputs and N outputs and including an optical switching fabric (S2-S2′), an input interface (S1) performing wavelength conversion and an output interface (S3) performing wavelength filtering. The input interface (S1) and the output interface (S3) are protected by redundancy provided by r redundant units for E working units where r is a number very much less than E.

Abstract: In communications systems having optical networks, data rates in the electrical domain can be matched to data rates in the optical domain by means of time-division multiplexing, with the pulses forming the transmitted optical data being compressed. A method performs the necessary pulse decompression on reception in all-optical manner. The method includes forming q auxiliary signals respectively obtained by amplitude modulating each of q optical carrier waves having different wavelengths by the received signal, and superposing q delayed auxiliary signals obtained by applying delays to the auxiliary signals such that any two consecutive delayed auxiliary signals are offset in time by the duration of the pulses making up the received signal.

Abstract: In order to re-synchronize and shape a binary signal of bit time T0, a method includes forming a number p of sampled signals obtained by causing the signal to modulate pulses that are of frequency 1/T0 and of duration substantially equal to T0/p, and that are carried by p optical carriers having different wavelengths. The method also includes combining delayed signals that are obtained by applying delays to the sampled signals, such that any two consecutive delayed signals are offset in time by T0/p. The method applies to optical communications systems.

Abstract: The invention relates to an optical transmission system comprising a transmission line which includes at least one optical fiber amplifier. According to the invention, a stabilized gain optical amplifier is coupled to the input of the line, said stabilized gain amplifier including a local oscillator suitable for emitting an auxiliary compensation wave at a wavelength .lambda.loc which lies in the gain band of each optical fiber amplifier of the line. Provision is also made to modulate the pumping current of said stabilized gain amplifier to convey service information. The invention is applicable to optical transmission.

Abstract: To perform selective dropping and adding of channels of wavelength multiplexes without interposing active elements in the main transmission path, the apparatus comprises add-and-drop modules, each of which includes at least one stop filter provided with two opposite ports. An optical switch provided with a drop outlet is provided with drop inlets and with add outlets associated with the modules, and respectively coupled to the opposite ports of the filters. For each module, the switch is organized for selectively coupling one of its drop inlets to one of its add outlets and/or to the drop outlet.

Abstract: The invention relates to a wavelength converter including an interferometer structure for delivering an output optical signal, in which converter a first branch contains a first semiconductor optical amplifier and a second branch contains a second semiconductor optical amplifier, the amplifiers being coupled to a common probe laser, and said first amplifier being organized to receive a modulating input signal, said converter including regulator means for acting on the total optical power delivered to said amplifier in response to a negative feedback signal representative of the extinction ratio of the output signal. The invention is applicable to making routing systems using wavelength-division multiplexing.

Abstract: In order to reduce its switching time, the delay apparatus comprises a coupler and a multiplexer provided with n inlets set respectively to n distinct wavelengths. Inlets of the multiplexer are coupled respectively to outlets of the coupler via wavelength conversion apparatuses, and via delay lines all of which are different. Each conversion apparatus has an amplifying optical gate function and delivers to the corresponding inlet of the multiplexer a wave carried by the wavelength associated with said inlet. The invention also concerns apparatus for synchronizing channels of a wavelength multiplex using the variable delay apparatus. Application in particular to synchronizing optical packets in a switched optical network.

Abstract: To simplify the connection protocols of an optical communication network using wavelength division multiplexing and to increase the throughput of the network, each node sends messages on a specific wavelength and associates destination labels with them. A network controller receives the messages and the labels and forwards the messages on the receive wavelength of their destination node(s). Applications include local area networks.

Abstract: To simplify the connection protocols of an optical communication network using wavelength division multiplexing and to increase the throughput of the network, each node sends messages on a specific wavelength and associates destination labels with them. A network controller receives the messages and the labels and forwards the messages on the receive wavelength of their destination node(s). Applications include local area networks.

Abstract: To shape binary optical signals, the apparatus comprises a first stage for providing a modulating signal whose high levels are stabilized so as to depend little on fluctuations in the input signal. The signal is applied to a second stage including an interferometer structure designed to deliver an output signal that is the result of interference between first and second auxiliary waves, the interference being respectively constructive and destructive when the power of the modulating signal corresponds respectively to a first logic state and to a second logic state. The apparatus can be used to modify the input signal by deleting or inserting data. It can be used in optical data switching or transmission.