Method and system for detecting loss of signal in wavelength division multiplexed systems
First Claim
1. In a wavelength division multiplex system having at least two nodes connected by a fiber path and the fiber path having at least one optical amplifier coupled thereto, a method for detecting at one of said nodes a fiber cut, said method comprising:
- generating a marker wavelength; and
detecting, at said one node, the power ratio between said generated marker wavelength and a nearby spectral band.
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Abstract
A method and system for unambiguously detecting fiber cuts in an optical network regardless of the number of EDFAs that are located between the fiber cut and the monitor point. In accordance with our invention, the power of a marker wavelength is compared to the power of a nearby spectral region. Where the comparison indicates that the power ratio is approximately equal to unity a flag is raised indicating that there is fiber cut. Where the comparison indicates that the power ratio is much greater than unity the flag is not raised. The monitoring point includes circuitry for detecting the ratio between the marker wavelength and the nearby spectral band and for indicating when there is a fiber cut.
49 Citations
20 Claims
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1. In a wavelength division multiplex system having at least two nodes connected by a fiber path and the fiber path having at least one optical amplifier coupled thereto, a method for detecting at one of said nodes a fiber cut, said method comprising:
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generating a marker wavelength; and detecting, at said one node, the power ratio between said generated marker wavelength and a nearby spectral band. - View Dependent Claims (2, 3)
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4. A system for detecting a fiber cut on a fiber having at least one fiber amplifier between a monitor point and the fiber cut, said system comprising:
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circuitry for generating a compensating channel; and circuitry for detecting the power ratio between the generated compensating channel and a spectral band having approximately the same gain as the compensating channel; said compensating channel circuitry and said detection circuitry being coupled to the fiber so that a cut at any location along the fiber is detected. - View Dependent Claims (5)
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6. A wavelength division multiplex system comprising:
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at least two node elements interconnected by a working and a standby fiber; a plurality of amplifiers in said fibers; and means for determining a fiber cut in one of said fibers, said means comprising means for comparing the power ratio between a marker wavelength on said one fiber and a nearby spectral band. - View Dependent Claims (7, 8, 9, 10)
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11. A wavelength division multiplex system comprising:
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at least two node elements interconnected by a working and a standby fiber; a plurality of erbium doped amplifiers in said fibers; means for determining a fiber cut in one of said fibers, said means comprising means for comparing the power ratio between a marker wavelength on said one fiber and a nearby spectral band; and wherein said marker wavelength is provided by the erbium doped amplifiers.
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12. A wavelength division multiplex system comprising:
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at least two node elements interconnected by a working and a standby fiber, said node elements being arranged in a point-to-point configuration; a plurality of amplifiers in said fibers, means for determining a fiber cut coupled to one of said fibers, said means comprising means for comparing the power ratio between a marker wavelength on said one fiber and a nearby spectral band; and means responsive to said determining means for switching from said working to said standby fiber.
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- 13. A method for detecting a fiber cut in a wavelength division multiplex system having at least one amplifier between two node elements, said method comprising comparing the power ratio at a monitoring point on the fiber between the power in a first spectral band and the power in an adjacent spectral band.
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19. A method for detecting a fiber cut in wavelength division multiplex system having at least one amplifier between two node elements, said method comprising comparing the power ratio at a monitoring point on the fiber between the power in a first spectral band and the power in an adjacent spectral band, wherein the detection of a power ratio approximately equal to unity indicates a fiber cut in said fiber,
wherein said first spectral region comprises a marker channel, and wherein said amplifier is an erbium doped fiber amplifier, said marker channel comprising a compensating channel of said amplifier and said second spectral region comprises the working signals of said fiber.
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20. A method for detecting a fiber cut in a wavelength division multiplex system having at least one erbium doped amplifier between two node elements, said method comprising comparing the power ratio at a monitoring point on the fiber between the power in a first spectral band and the power in an adjacent spectral band, and wherein
said first spectral region comprises amplified spontaneous emission of said amplifier and said second spectral region comprises the working channels of said fiber.
Specification