France Telecom

France Telecom Etablissement Autonome De Droit Public

France Telecom Establissement Autonome De Droit Public

French State Represented by the Minister of Post, Telecommunications and

Andre Hamel

Daniel Laville

Henri Porte

Jean-Pierre Goedgebuer

Valerie Tholey

Philippe Guignard

Emile F Le Coquil

Jean Stoschek

Eric Delevaque

Jean-Claude Simon

Guignard Philippe

Laurent Blain

Alain Sutter

This network, intended for the transmission of information in optical form, wavelength multiplexed, comprises nodes (N1, N2) linked to each other by at least one optical fiber (F1), at least one wavelength being treated in each node. The system comprises unit (OF1, OF2, OS1, OS2) for superimposing on the information, for at least one wavelength per node, a surveillance signal whose frequency is outside the transmission band and, in each node, a surveillance circuit (CS1, CS2) for sampling at least one part of the surveillance signals, elaborating surveillance information in function of this part and sending this information to the processing units of the network. Application in optical telecommunications.

Surveillance system of a multi-wavelength ring network

This device includes optical add-drop multiplexers (M1 to M2) each having a band-pass filter. An optical switch (C1) has outputs connected to the multiplexers. An optical coupling (C2) has inputs connected to the multiplexers. The device is useful in optical communications.

Reconfigurable device for insertion-extraction of wavelengths

This ring network for wavelength-multiplexed information transmission. comprises two optical fibres (F1, F2) passing through nodes (N1 to N4) of the network and traversed in the opposite direction by informations, electronic add-drop multiplexers (ME1 to ME4) or ADM, each ADM supplying information to other ADM's, of the network at given wavelengths and optical add-drop multiplexers (M01 to M04) or OADM, each OADM adding to the fibres the informations from the associated ADM and extracting from said fibres the informations intended for said ADM. Application to optical telecommunications.

Ring network for transmitting wavelength-multiplexed informations

Optical component adapted to monitor a multiwavelength link for use as an add-drop multiplexer in optical networks. The optical component includes an input fiber (68) for transmitting signals of different wavelengths, a diffraction grating (70) for dispersing these signals on several orders of diffraction, fibers (72, 74, 76 and 78) for recovering the dispersed signals corresponding to a given order of diffraction, and fibers (79, 80, 82, and 84) for recovering the same signals but corresponding to another order of diffraction so as to monitor the state of these signals.

Optical component adapted to monitor a multiwavelength link and add-drop

According to the invention, a first band-pass multidielectric filter (F1) receives optical signals, transmits at least one of them and reflects the untransmitted signals. An adding means (F2) inserts among them at least one other optical signal. A photoinduced Bragg grating filter (R) receives the signals reflected by the first filter and transmits them to the adding means and reflects any optical signal of the same wavelength as the signal transmitted by the first filter and which is liable to exist among the signals reflected by it. Application to optical telecommunications.

High isolation, optical add-drop multiplexer

The network according to the invention combines a circuit switching multicoloured optical network (R1) and a packet switching network (R2). The circuit switching network is adapted to transmit data at a high rate. The packet switching network is adapted to transmit data at an average rate. Control data are carried on the packet switching network. This provides more efficient transmission of data and effectively handles peak transmission rates. The invention has application to telecommunications.

Telecommunications system combining wavelength multiplexing and packet

An add-drop multiplexer includes a first photodector (14), which receives informations in optical form, some of which are to be supplied to users addressees or recipients chosen from among N users addressees or recipients associated with the wavelengths L1, . . . , LN, whilst the other informations form an output flow at wavelength LO, a second photodetector (16) receiving in optical form informations to be inserted in said flow, a tunable source (18), which converts the signals from the first photodetector into optical signals of wavelengths chosen from among LO, L1 . . . LN under the control of control unit (20) and as a function of their destination, another source (22), which converts the signals from the second photodetector into optical signals of wavelength LO, a coupler (24) connecting the sources to N+1 filters (f0 . . . , f3) only respectively permitting the passage of LO . . . LN. Application to optical telecommunications.

Add - drop multiplexer

According to the present invention, an optical communications network is provided, which network comprises control means for controlling the network and a plurality of stations each having an information emitter and receiver. The stations are interconnected by optical signal transmission supports and the control means. According to the present invention, main delays of the stations are controllably modifiable, as desired, by the control means. Particular utility is found in the area of private communications networks, although other utilities are contemplated.

Optical communications network

An optical distributor which comprises M inputs (M&gt;1) each receiving signals. M modules (MT1 to MT4) are connected to the M inputs and each simultaneously process N consecutive signals (N&gt;1). N optical couplers (CO1 to CO4) each having M inputs and 1 output are connected to one of the N outputs. A control means (G) controls the modules and enables the distributor to scramble the signals so that a given signal reaches a given output of the distributor. Each module electronically demultiplexes the N consecutive signals, time rearranges the demultiplexed signals in accordance with the output of the distributor imposed by the control means for each of these signals, transposes the latter into optical form at N different wavelengths and switches each transposed signal to the desired output of the distributor. Such a device finds particular application in optical telecommunication system.

Optical distributor

A multi-purpose component with integrated optics includes an optical light guide (12) formed on one face of a substrate (10) made of a double refracting material having neutral axes orientated so that one electromagnetic wave extending into the guide (12) is split up into two waves having polarizations perpendicular to each other and along the neutral axes. A power source (18) applies an electric filed perpendicular to the optical light guide (12) and uniformly along the guide (12). Two rectilinear polarizers (20, 22) with polarization directions (d1, d2) parallel to each other are each disposed at one extremity of the guide (12). The component also includes focussing means (24, 26, 28, 30). The component has particular utility for tuneable optical filtering and optical telecommunications.

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Lannion, France

Andre Hamel