Single-end polarization mode dispersion measurement using backreflected spectra through a linear polarizer

Routine characterization of polarization mode dispersion of single-mode fibers in installed cables requires simple and fast techniques. All standardized techniques use both fiber ends, one connected to the optical source and the other one for signal detection. Clearly, this causes several drawbacks in field tests because the two fiber ends are usually far from each other. Among standardized techniques, the fixed-polarizer method (also called wavelength scanning method) is one of the simplest to implement. In this work we present a new single-end measurement scheme based on the fixed polarizer method applied to the signal backreflected by the fiber far-end. We report analytical equations and numerical solutions that permit to calculate the mean value of the differential group delay measuring the crossings and/or extreme densities of the spectrum transmitted through a linear polarizer. We also show that the mean value of the differential group delay can be calculated using the Fourier transform of the detected signal. Finally, experimental results on cascades of single-mode step-index fibers confirm the robustness and easiness of our proposal for polarization mode dispersion measurements.