Spatially resolved PMD measurements

Spatially resolved measurements of polarization properties of fiber optic link-such as birefringence, polarization-mode dispersion (PMD) and polarization dependent loss (PDL)-may be effectively performed using polarization sensitive reflectometric techniques. In particular, this paper focuses on polarization-OTDR and reviews its theory and applications. Special emphasis is given to the use of optical reflectometry as a tool to characterize fiber birefringence. This allows to inspect the fiber while cabled and, consequently, to test and improve the cabling process. In addition, it also allows to define reliable mathematical models, which are essential for the design of low polarization mode dispersion fibers. The application of polarization-OTDR to polarization mode dispersion and polarization dependent loss measurements is also discussed.