Abstract: A method includes, for each optical fiber path in an optical network, allocating an optical wavelength channel in an optical spectrum such that the allocated optical wavelength channel is assigned to support optical communications over the optical fiber path. The method also includes updating an allocation table in response to performing the allocating for one or more of the optical fiber paths; the allocating including determining the optical wavelength channel to be allocated based on a state of the allocation table. The allocation table indicates optical wavelength channels allocated over optical fiber spans of the optical network. The method also includes defining a set of optical sub-bands to cover a part of the optical spectrum in response to a state of the allocation table satisfying a fullness property. The optical sub-bands are such that each of the allocated wavelength channels is in one of the optical sub-bands.

Abstract: 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step, a reduced set of candidate optical connections is defined by withdrawing the candidate optical connection to be withdrawn.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.

Abstract: 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step, a reduced set of candidate optical connections is defined by withdrawing the candidate optical connection to be withdrawn.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.

Abstract: The device includes a decision circuit (6a) 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 (12) 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 (15) 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.

Abstract: 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 (Ci), 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.

Abstract: 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×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.

Abstract: 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.

Abstract: An optical demultiplexer system for separating adjacent wavelength bands without losing inter-band channels and comprising a first filter stage (210) 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 (240) 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.

Abstract: The device includes a decision circuit (6a) 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 (12) 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 (15) 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.

Abstract: An optical demultiplexer system for separating adjacent wavelength bands without losing inter-band channels and comprising a first filter stage (210) 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 (240) 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.

Abstract: An optical multiplexer device (D) is dedicated to inserting/dropping optical resources for an optical transmission line comprising an upstream fiber (F1) and a downstream fiber (F2).

Abstract: The present invention relates to the field of optical telecommunications networks, and more particularly to a method and to devices for backing up a ring optical telecommunications network. The method of the invention corresponds to a method of backing up a ring optical telecommunications network including a traffic concentrator (1) and a communications node (N3) interconnected by an optical fiber (2) (s1, s2) transported in the fiber and addressed to the node. The method of the invention comprises the following successive steps: while the network is being set up, a step of creating a virtual break (C) between the concentrator and the node; and when an at least partial real break in the fiber is detected that limits or interrupts the transmission of the signals to the node, a step of displacing the virtual break so that it coincides with the real break so as to re-establish the reception of the optical signals by the node.

Abstract: An optical multiplexer device (D) is dedicated to inserting/dropping optical resources into or from an optical transmission line comprising incoming and outgoing optical fibers (F1, F2).

Abstract: 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.

Abstract: An optical system is dedicated to dynamically measuring power loss in an optical fiber (FO) having a first end (E1) and a second end (E2) respectively adapted to receive and to send primary optical signals. The system comprises injection means (3) adapted to inject supervisory signals into the second end (E2) of the optical fiber (FO) at a selected optical power and detection means (5) adapted to extract the supervisory signals at the first end (E1) of the optical fiber (FO) in order to determine their optical power and to deduce therefrom and from the selected optical power primary information representative of the optical power loss of the supervisory signals in the optical fiber (FO), and where applicable to compare the primary information to a value representative of a nominal power loss in the optical fiber (FO) in order to supply secondary information representative of a variation of the power loss in the optical fiber.

Abstract: An optical system dynamically measures power loss in an optical fiber (2) 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 (4) 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 (7) 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.

Abstract: A method is disclosed of reconfiguring a ring optical network made using a single optical fiber (100). A traffic concentrator (120) and stations (140) 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 (110, 150) in order to be able to communicate with all the stations. When the network is established, a virtual break (170) 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 (400) for changing the direction of the light signals.

Abstract: 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 (Ci), 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.

Abstract: The optical device is for measuring and dynamically compensating power loss variations in an optical fiber (2). It includes injector means (4) adapted to inject supervisory signals having a chosen optical power downstream of the fiber entry end (E) and detector means (5) adapted to extract the supervisory signals at the exit end (S) of the fiber (2), to determine their optical power, to deduce therefrom and from said chosen optical power primary information representative of the optical power loss of the supervisory signals in the fiber, and to compare said primary information and a value representative of a nominal power loss in the fiber to deliver secondary information representative of a variation in the power loss in the optical fiber (2). Control means (11) coupled to the detector means (5) and to the exit end (S) of the fiber (2) modify the power of the primary signals delivered by the exit end of the fiber (2) as a function of the detected variation in power loss.

Abstract: An optical system dynamically measures power loss in an optical fiber (2) 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 (4) 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 (7) 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.