Add/drop multiplexer routing signals according to wavelength
AssigneeAlcatel
InventorsKevan Peter Jones, Martin J. Pettitt
Life of this patent
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Abstract
An add/drop multiplexer comprises passive optical components for wavelength division multiplexing. The multiplexer allows signals passing along fibers of a main trunk between terminal stations to be dropped to and added from a spur station, allowing a reduced number of spur fibers to be used since signals are routed between trunk fibers and spur fibers according to carrier wavelength.
Claims85
An add/drop multiplexer for use in optical wavelength division multiplexing, the add/drop multiplexer having a first trunk input for receiving traffic signals from a first part of a first trunk fibre, a second trunk input for receiving traffic signals from a first part of a second trunk fibre, a first trunk output for outputting traffic signals to a second part of the first trunk fibre, a second trunk output for outputting traffic signals to a second part of the second trunk fibre, and at least one branch input/output for outputting signals to and inputting signals from a branch fibre;
- the add/drop multiplexer comprising:
- means for routing from the first trunk input to a first one of said at least one branch input/outputs a first set of traffic signals at carrier wavelengths predetermined for transmission of signals from the first trunk fibre to the branch station and for routing from the first one of said at least one branch input/outputs to the trunk output of a first one of said first and second trunk fibres a second set of traffic signals at carrier wavelengths predetermined for transmission of signals from the branch station to said first one of the first and second trunk fibres.
An add/drop multiplexer for use in an optical wavelength division multiplexing system in which specific carrier wavelengths are assigned for transmission between different stations in the system, said add/drop multiplexer comprising:
- a first trunk input port for receiving traffic signals from a first part of a first trunk fibre of the system and a first trunk output port for providing traffic signals to a second part of said first trunk fibre;
- a second trunk input port for receiving traffic signals from a first part of a second trunk fibre of the system and a second trunk output port for providing traffic signals to a second part of said trunk fibre;
- a branch input port for receiving traffic signals from a branch input fibre and a branch output port for providing traffic signals to a branch output fibre;
- signal splitting means to split the traffic signals input from each of said input ports into signals for provision to selected output ports in accordance with a routing determined by the carrier wavelengths of said traffic signals;
- signal coupling means for providing output traffic signals at each of said output ports, wherein for each one of said trunk output ports traffic signals from the corresponding trunk input port and from the branch input port at carrier wavelengths selected for routing to that trunk output port are combined for output to that trunk fibre, and wherein for the branch output port traffic signals from the trunk input ports at carrier wavelengths selected for routing to the branch station are combined for output on the branch output fibre.
An add/drop multiplexer for use in an optical wavelength division multiplexing system in which the routing of traffic signals is determined by specific carrier wavelengths provided for said traffic signals, said add/drop multiplexer comprising:
- three or more four port optical circulators, respective ports of each optical circulator being connected to form a network;
- an input port and an output port for a first trunk fibre, for providing signals to and receiving signals from, respectively, designated ports of said three or more optical circulators;
- an input port and an output port for a second trunk fibre, for providing signals to and receiving signals from, respectively, designated ports of said three or more optical circulators;
- an input port and an output port for each of one or more branch fibres, for providing signals to and receiving signals from, respectively, designated ports of said three or more optical circulators;
- wherein one or more notch reflection filters are provided on said network between adjacent optical circulators for transmission of signals at predetermined ones of said specific carrier wavelengths and for reflection of signals at others of said specific carrier wavelengths, thereby routing signals from said input ports to designated ones of said output ports.
An add/drop multiplexer for use in an optical wavelength division multiplexing system, said add/drop multiplexer comprising a plurality of interconnected basic multiplexer units,
- each said basic multiplexer unit comprising a first input, a first output, a second input and a second output, and further comprising routing means such that signals at one or more predetermined carrier wavelengths are routed from the first input to the second output and from the second input to the first output, but such that signals at other carrier wavelengths are routed from the first input to the first output and from the second input to the second output.
Add/drop multiplexer for use in optical wavelength division multiplexing, said add/drop multiplexer having a first trunk input port for receiving traffic signals from a first part of a first trunk fibre and a first trunk output port to provide traffic signals to a second part of the first trunk fibre, a second trunk input port for receiving traffic signals from a first part of a second trunk fibre and a second trunk output port to provide traffic signals to a second part of the second trunk fibre, and first and second branch input/output ports for receiving signals from and providing signals to branch fibres, wherein the add/drop multiplexer is adapted both to input one or more branch input signals and output one or more branch output signals at each of said input/outputs.
Add/drop multiplexer for use in optical wavelength division multiplexing, said add/drop multiplexer having a first trunk input port for receiving traffic signals from a first part of a first trunk fibre and a first trunk output port to provide traffic signals to a second part of the first trunk fibre, a second trunk input port for receiving traffic signals from a first part of a second trunk fibre and a second trunk output port to provide traffic signals to a second part of the second trunk fibre, and first and second branch ports for receiving signals from and providing signals to a branch station, wherein the add/drop multiplexer comprises:
- a first and a second five-port optical circulator for routing according to carrier wavelength to the branch station via the branch ports designated signals from the first and second trunk input ports, and for routing according to carrier wavelength to the first and second trunk output ports designated signals from the branch ports.
A fibre optic network, comprising two terminal stations, at least two trunk fibres for connecting said two terminal stations, at least one branch station each connected by a spur fibre to a fibre trunk defined by said two trunk fibres, and at least one branching unit on the fiber trunk to allow exchange of traffic signals between said trunk fibres and one or more of said spur fibres, wherein said branching unit comprises:
- an add/drop multiplexer for use in optical wavelength division multiplexing, the add/drop multiplexer having a first trunk input for receiving traffic signals from a first part of a first trunk fibre, a second trunk input for receiving traffic signals from a first part of a second trunk fibre, a first trunk output for outputting traffic signals to a second part of the first trunk fibre, a second trunk output for outputting traffic signals to a second part of the second trunk fibre, and a branch input for receiving traffic signals from a branch input fibre, and/or a branch output for outputting traffic signals to a branch output fibre;
- the add/drop multiplexer comprising at least one of:
- means for routing from the first trunk input to the branch output of first set of traffic signals at carrier wavelengths predetermined for transmission of signals from the first trunk fibre to the branch station and for routing from the second trunk input to the branch output a second set of traffic signals at carrier wavelengths predetermined for transmission of signals from the second trunk fibre to the branch station, and means for combining said first and second sets of traffic signals for output at the branch output;
- and or
- means for separating traffic signals received at the branch input into a third set of traffic signals at carrier wavelengths predetermined for transmission of signals from the branch station to the first trunk fibre and a fourth set of traffic signals at carrier wavelengths predetermined for transmission of signals from the branch station to the second trunk fibre, and means for routing the third set of traffic signals to the first trunk output and the fourth set of traffic signals to the second trunk output respectively.
Dependencies are inferred from the claim text.