Application of Crossed Polarizer Method in the Measurement of Differential Group Delay of Optical Fibers

In this paper, we report the use of crossed polarizer technique to measure differential group delay (DGD) few-mode optical fiber (FMF). The windowed Fourier transform (WFT) is applied in analysis beat length measurement spectral domain obtain dependence DGD as a function wavelength. birefringence polarization-maintaining (PMF) and FMF are measured by applying our method. We discuss noise background, width peaks, possible errors introduced path modified technique.