Monitoring eDC polarization inverse filter coefficients to identify real-time physical intrusion into a core or metro optical network
First Claim
1. A method of monitoring a physical condition of an optical waveguide, the method comprising:
- monitoring, at a state of polarization logic module, dispersion compensation coefficients to determine changes in a state of polarization of an optical signal propagating on the optical waveguide during a time interval; and
when the state of polarization is determined to change by more than an amount of drift expected during the time interval, generating a signal at the state of polarization logic module to indicate that the physical condition of the optical waveguide has changed.
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Accused Products
Abstract
A fiber network is monitored in order to detect physical intrusion. The state of polarization of an optical fiber is monitored. A fiber tap is determined to have occurred if the state of polarization of the fiber changes beyond a predetermined amount found to be associated with all types of fiber taps. Alternately, it may be determined that a fiber tap has occurred if the state of polarization changes beyond a second predetermined amount and in a predetermined direction. Monitoring of the state of polarization occurs before and after a time period chosen to be less than a time during which the state of polarization of the optical fiber is expected to drift. This step eliminates false positives due to natural fiber PMD drift.
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Citations
9 Claims
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1. A method of monitoring a physical condition of an optical waveguide, the method comprising:
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monitoring, at a state of polarization logic module, dispersion compensation coefficients to determine changes in a state of polarization of an optical signal propagating on the optical waveguide during a time interval; and when the state of polarization is determined to change by more than an amount of drift expected during the time interval, generating a signal at the state of polarization logic module to indicate that the physical condition of the optical waveguide has changed. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method of monitoring a physical condition of an optical waveguide, the method comprising:
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monitoring, at a state of polarization logic module, dispersion compensation coefficients to determine changes in a state of polarization of an optical signal propagating on the optical waveguide during a time interval; and when the state of polarization is determined to change by more than a predetermined amount during the time interval, generating a signal at the state of polarization logic module to indicate that the physical condition of the optical waveguide has changed. - View Dependent Claims (8, 9)
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Specification