Field measurements of PMD using four measurement techniques

In the last 10 years, Telcordia has conducted numerous first-order PMD (polarization mode dispersion) measurements of installed optical fibers at various locations throughout North America. The measurements were made by using test instruments based on interferometric method. This work has been reported in detail in the past NFOEC symposia. The results have been analyzed with respect to various cable designs, type of outside plant, year of manufacture, and cable manufacturers. Recently, Telcordia has had the opportunity to make additional PMD measurements on previously characterized optical fibers. The new Telcordia measurements were made by using test instruments based on four measurement techniques. The recent PMD measurements include equipment that uses the following PMD measurement techniques: wavelength scanning (fixed analyzer) with cycle counting, Jones matrix eigenanalysis, wavelength scanning (fixed analyzer) with Fourier transform, and interferometry. According to TIA (Telecommunications Industry Association) inter-laboratory round-robin PMD tests, the four methods above yield systematic and random disagreement between measurements of within ± 10 % to ± 20 %. This variability is stated as state-of-the-art by TIA/EIA in their FOTPs (fiber optic test procedures) describing PMD measurement methods. The new Telcordia PMD measurements are expected to provide significant additional insight as to the relationship between the four PMD test methods listed above and help contribute to the general understanding of the major approaches to modern PMD measurement techniques.