Choices ease PMD test burden

摘要

One of the biggest myths surrounding polarization mode dispersion (PMD) is that it is only an issue with old fibers installed more than about 10 years ago. However, experience shows that there can be problems with cables that were installed during the optical boom when the established, reputable fiber manufacturers were unable to meet the demand for quality fiber. Poor-quality fiber that would otherwise have been scrapped found its way onto the market; fiber was also procured from other sources around the world whose fiber manufacturing processes and procedures were not as well controlled as those of the major vendors. In fact, the record for the worst fiber this writer has ever tested comes from this era: Can anyone beat a figure of 27 psec/√km for the PMD coefficient of an installed fiber link?