Methods and systems for controlling fiber polarization mode dispersion (PMD)
View Patent ↗A method is provided for predicting an installed performance parameter of an optical fiber cable. The method includes obtaining a measurement indicative of a value of the performance parameter at a first moment in time. A measurement indicative of a value of the performance parameter at a second moment in time may then be obtained. A first correlation may then be determined between the measurement at the first moment in time and the measurement at the second moment in time. A value of the performance parameter at the second moment in time may then be estimated based upon the measurement at the first moment in time in combination with the first correlation, the first correlation being based upon observations of a manner in which the performance parameter varies over time for at least a second optical fiber.
1. A method for predicting an installed performance parameter of an optical fiber cable, comprising:
obtaining a measurement indicative of a value of the performance parameter at a first moment in time;
obtaining a measurement indicative of a value of the performance parameter at a second moment in time;
determining a first correlation between the measurement at the first moment in time and the measurement at the second moment in time; and
estimating a value of the performance parameter at the second moment in time based upon the measurement at the first moment in time in combination with the first correlation,
the first correlation being based upon observations of a manner in which the performance parameter varies over time for at least a second optical fiber.
2. The method of claim 1 , wherein the first moment in time occurs during manufacture of the optical fiber cable and the second moment in time occurs subsequent to manufacture of the optical fiber cable.
3. The method of claim 1 , further comprising:
obtaining a measurement indicative of a value of the performance parameter at an nth moment in time, where n is an arbitrary integer and wherein the nth moment in time represents any moment in time; and
determining a second correlation between a first measurement selected from the measurement at the first moment in time, the second moment in time, or the nth moment in time and a second measurement selected from the measurement at the first moment in time, the second moment in time, or the nth moment in time.
4. The method of claim 1 , further comprising:
determining the second correlation between the measurement at the second moment in time and a measurement at a third moment in time.
5. The method of claim 3 , further comprising:
estimating a value of the performance parameter at an mth moment in time based upon the measurement at the first moment in time and the first and second correlations, where m is an arbitrary integer.
6. The method of claim 3 , further comprising:
identifying at least one sensitive moment in time from the first, second and nth moments in time; and
estimating a value of the performance parameter at an mth moment in time based upon the measurement at the sensitive moment in time and the first, second and third correlations, where m is an arbitrary integer.
7. The method of claim 3 , further comprising:
determining a generic correlation using the first and second correlations; and
estimating a value of the performance parameter at an mth moment in time based upon the generic correlation, where m is an arbitrary integer.
8. The method of claim 3 , wherein the first moment in time occurs during manufacture of the optical fiber cable, the second moment in time occurs during the cabling of the optical fiber cable, and the nth moment in time occurs during installation of the optical fiber cable.
9. The method of claim 1 , further comprising:
determining if the measurement indicative of the value of the performance parameter at the first moment in time meets or exceeds a first predetermined threshold;
removing the optical fiber cable if it is determined that the measurement indicative of the value of the performance parameter at the first moment in time does not meet or exceed the first predetermined threshold; and
analyzing the optical fiber cable to determine a root cause for failure.
10. The method of claim 1 , further comprising:
generating a first histogram indicative of the measurement at the first moment in time; and
generating a second histogram indicative of the measurement at the second moment in time.
11. The method of claim 1 , further comprising:
generating a square of the correlation coefficient to provide a proportion of a variance of the measurement at the second moment in time explained by a variance at the first moment in time; and
estimating the value of the performance parameter at the second moment in time based upon the measurement at the first moment in time in combination with the first correlation and the square of the correlation coefficient.
12. The method of claim 1 , wherein
the measurement at the first moment in time includes a plurality of measurements at the first moment in time; and
the measurement at the second moment in time includes a plurality of measurements at the second moment in time.
13. The method of claim 12 , further comprising:
generating a regression equation representing a linear relationship between the plurality of measurements at the first moment in time and the plurality of measurements at the second moment in time; and
estimating the value of the performance parameter at the second moment in time based on a subsequent measurement at the first moment in time in combination with the regression equation.
14. The method of claim 1 , wherein the performance parameter is polarization mode dispersion (PMD).
15. The method of claim 14 , wherein PMD is measured using a Jones Matrix Eigenanalysis (JME) method.
16. The method of claim 14 , wherein PMD is measured using a wavelength scanning method.
17. The method of claim 14 , wherein PMD is measured using a interferometric method.