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US 6,285,475 B1Granted
Method and system for detecting optical faults in a network fiber link
AssigneeMCI Communications Corporation
InventorJohn Arthur Fee
Life of this patent
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AssigneeMCI Communications Corporation
InventorJohn Arthur Fee
Estimating the term…
A method and system for detecting optical faults by tapping a portion of a data signal from along a fiber network link at an optical switching site or node. The tapped data signal is evaluated to determine whether an optical fault exists along the fiber link. In this way, optical faults such as a fiber failure, cable cut, or nodal LTE failure occurring within a network path, are isolated to a specific fiber span or link. Network switch controllers can then take full advantage of optical switches provided between spans in an all-optical core network to restore end-to-end path communication. In one embodiment, a presence detector simply evaluates the magnitude of the tapped signal to determine an optical fault. In a second embodiment, a protocol analyzer evaluates selected bits or fields of the protocol used in the tapped data signal to determine an optical fault. Finally, in a third embodiment, a sub-carrier modulation signal is added to the high rate data signal prior to transport over the link. The subcarrier signal is significantly lower in both frequency and amplitude than the main data signal so as to not impact reliable reception of the main data signal. A low-pass filter tuned to the sub-carrier modulation signal filters the tapped data signal. By detecting the sub-carrier signal, fault can be determined inexpensively and reliably in the presence of optical noise.
A method for detecting an optical fault in a communication network, wherein the communication network includes first and second sites connected by a first fiber link carrying a modulated optical data signal between the first and second sites, the second site further including an intermediate optical cross-connect switch for optically coupling the modulated optical data signal between said first fiber link to a second fiber link, comprising the steps of:
An apparatus for detecting an optical fault in a communication network, wherein the communication network includes first and second sites connected by a first fiber link carrying a modulated optical data signal between the first and second sites, the second site further including an intermediate optical cross-connect switch for optically coupling the modulated optical data signal between said first fiber link to a second fiber link, comprising:
An apparatus for detecting an optical fault in a fiber link carrying a modulated optical data signal between first and second network sites, comprising:
A method for detecting an optical fault in a communication network, wherein the communication network includes first and second sites connected by a first fiber link carrying a modulated optical data signal between the first and second sites, the second site further including an intermediate optical cross-connect switch for optically coupling the modulated optical data signal between the first fiber link and a second fiber link, comprising the steps of:
An apparatus for detecting an optical fault in a communication network, wherein the communication network includes first and second sites connected by a first fiber link carrying a modulated optical data signal between the first and second sites, the modulated optical data signal propagating along the fiber link at an optical carrier wavelength, and the second site further including an intermediate optical cross-connect switch for optically coupling the modulated optical data signal between the first fiber link and a second fiber link, comprising:
An apparatus for detecting an optical fault in a fiber link carrying a modulated optical data signal between first and second network sites, the modulated optical data signal propagating along the fiber link at an optical carrier wavelength, comprising:
Dependencies are inferred from the claim text.