Polarization mode dispersion measurements in an installed optical fiber submarine cable

Highly accurate polarization mode dispersion (PMD) measurement using an interferometric detection technique with AC modulation is discussed. This technique, which searches for the interference fringe signal, was used to measure PMD in a 60 km long installed optical submarine cabled fiber 2500 m sea depth and to determine the fiber-length dependence of PMD. PMD measurement in 60-km-long installed optical submarine cabled fibers was confirmed to be less than about 0.7 ps. It was found that the fiber length dependence of the PMD measurement in the less than approximately 20-km-long cascaded uncabled fibers was proportional to square root L; however, the PMD data in the long-length (over approximately 50 km long) fibers were slightly scattered.< >