Alcatel

Alcatel Lucent

Arnaud Bisson

Ludovic Noirie

Jean-Paul Faure

Guy Balland

Alice Michaud

Emmanuel Rossi

Nicolas Le Sauze

Amaury Jourdan

Annalisa Morea

Franck Bruyere

Omar Ait Sab

Sabry Khalfallah

Jean-Claude Jacquinot

Luc Berthelon

Patricia Layec

An exemplary technique is provided for planning a plurality of optical connections as a function of a plurality of traffic demand. In a routing step, a loopless network path is allocated to each traffic demand. Each traffic demand is allocated to a candidate optical connection or chain of candidate optical connections selected to carry the capacity of the traffic demand along the loopless network path allocated to the traffic demand. In an optimization step, a reduced set of candidate optical connections is defined by withdrawing the candidate optical connection to be withdrawn. A candidate optical connection or a chain of candidate optical connections is determined to be re-used among the reduced set of candidate optical connections. The traffic demand is re-allocated to the candidate optical connection or chain of candidate optical connections to be re-used.

Planning of optical connections in a WDM optical network

The device includes a decision circuit () for providing, by comparing the amplitude of a received modulated signal (Sr) to a decision threshold (Vth, Th), a binary signal (Sb) with two states respectively representing first and second binary values that respectively correspond to low and high values of the received signal. A counting module () activated during successive time periods calculates a differential numerical value (DN, SDN) representing the algebraic difference between the two numbers of bits of the binary signal that respectively have the second binary value and the first binary value. At the end of each time period, an adjustment module () increases or decreases the threshold value (Vth, Th) by an increment (Dth) according to whether the sign (SDN) of the difference is respectively positive or negative. Application in particular to systems for transmitting digital data at high bit rates over optical connections.

Analog-to-digital converter with a decision circuit and an optimized decision threshold

The present invention relates to a method of monitoring the transmission of optical signals including a step of inserting a monitoring signal (S) more particularly suited to monitoring the quality of service. During the transmission of optical signals each carried by a predefined wavelength defining a transmission channel (C), said signals are grouped onto the same fiber in a band (B) of channels. The method then includes a step of simultaneously modulating said signals grouped in the band of channels using the monitoring signal to be transmitted, so that each of the signals constitutes a carrier of the monitoring signal.

Method and a system for monitoring the transmission of optical signals

A reconfigurable directional optical system comprises N ports that can be configured individually as inputs or outputs. A system of this kind comprises at least one optical device having unidirectional inputs and outputs the total number of which is equal to or less than N, and an N&#xd7;N optical switch such that each of the ports can be coupled interchangeably either to one of the inputs or to one of the outputs of the optical device.

Reconfigurable directional optical system

An optical multiplexer device is dedicated to inserting/dropping optical resources for an optical transmission line comprising an upstream fiber and a downstream fiber. The device comprises: first and second OMADs each having a first primary inlet/out1et connected to the upstream or downstream fiber, and to L internal demultiplexing channels connected to L first secondary inlets/outlets, and a second primary inlet/outlet connected to M internal multiplexing connected to M second secondary inlets/outlets, connected to M send or receive modules L external coupling channels interconnecting the L first secondary inlets/outlets, and each fitted with a respective VOA capable of placing itself in a through or blocking state for allowing or preventing an optical resource to be transferred between OMADs; and an external drop or insert channel connected to the upstream or downstream fiber, respectively, and to the first primary or second primary inlet/outlet of the second or first OMAD, respectively.

Compact and reconfigurable optical device for controlled insertion/dropping of optical resources

An optical demultiplexer system for separating adjacent wavelength bands without losing inter-band channels and comprising a first filter stage () of relatively narrow passband and relatively high selectivity in order to extract all of the inter-band channels. The first stage is followed by a second filter stage () of relatively broad passband and relatively low selectivity to extract the wavelength bands delivered by the first filter stage. Such a system makes it possible to use the inter-band channels, in particular for managing the network and the wavelength bands.

System for optically demultiplexing wavelength bands

An optical device that measures and dynamically compensates power loss variations in an optical fiber based on supervisory signals. An injector injects supervisory signals having a predefined optical power downstream of the fiber entry end and a detector extracts the supervisory signals at the exit end of the fiber to detect their optical power. Based on the detected optical power and the predefined optical power, the optical power loss of the supervisory signals in the fiber is determined. The optical power loss and the nominal power loss in the fiber are compared to determine a variation in the power loss in the optical fiber. A controller coupled to the detector and to the exit end of the fiber modifies the power of primary signals delivered by the exit end of the fiber as a function of the detected variation in power loss.

Device for measuring and dynamically compensating variations in power loss in an optical transmission line with a supervisory channel, and an associated method

An optical system dynamically measures power loss in an optical fiber () having an entry end (E) adapted to receive optical signals and an exit end (S) adapted to deliver the signals. The system comprises modulation means () upstream from the entry end (E) and adapted to modulate the amplitude of the optical signals with a low-frequency modulation signal having a modulation index inversely proportional to the input power (Pe) of the optical signals, and detection means () downstream from the exit end (S) and adapted to extract from the modulated optical signals primary information representative of the output amplitude of the modulation signal and to deduce from the primary information secondary information representative of a variation in the power loss in the fiber.

System for measuring and/or dynamically controlling power loss in an optical transmission line, and an associated method

A method is disclosed of reconfiguring a ring optical network made using a single optical fiber ( ). A traffic concentrator ( ) and stations ( ) are optically connected to the fiber. The concentrator sends a light signal to and receives a light signal from both ends of the fiber using two groups of wavelengths ( ) in order to be able to communicate with all the stations. When the network is established, a virtual break ( ) is created between two stations. If a real break is detected in the optical fiber, then the virtual break is shifted until it coincides with the real break, thereby enabling traffic to be re-established between the concentrator and the stations. Each station is equipped with a three-state optical switch ( ) for changing the direction of the light signals.

Method and a system for protecting data transmitted on an optical ring formed of a single optical fiber

A device for erasing overhead modulation of an optical signal, wherein said optical signal is injected into an optical device able to modulate the optical signal (for example a semi-conductor optical amplifier driver by a bias control) and for which one an automatic gain control does not need to detect the residual overhead modulation, is characterised in that said bias control means applies to said amplifier a compensation voltage presenting a modulation out of phase with respect to said overhead modulation, and in that modulation index of said compensation voltage is (substantially) proportional to the modulation index of said optical signal.

Device for erasing overhead modulation of an optical signal

In particular for selectively dropping and/or inserting channels of a wavelength division multiplex, while minimizing losses, the apparatus includes,stop filters and optical switching means provided with n&plus;1 inlet ports of ranks 0 to n, and n&plus;1 outlet ports of ranks 1 to n&plus;1, as well as a set of waveguides making it possible to couple each outlet port selectively to one of said inlet ports of lower rank. Each filter is provided with first and second opposite ports coupled respectively to an associated outlet port and to an associated inlet port of the same rank. Application to optical transmission, in particular for performing routing operations.

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Orsay, France

Arnaud Bisson