Measurement of the differential group delay in installed optical fibers using polarization multiplexed solitons

We experimentally demonstrate a new technique for measurement of the differ ential group delay (DGD) in optical fibers using polarization-division mult iplexed (PDM) solitons: the change in the separation of orthogonally polari zed solitons propagating along different principal axes in a fiber equals t he DGD at the signal wavelength. Based on this principle, we use PDM solito ns to measure the accumulated DGD at different distances along a 400-km ins talled fiber. The measured DGD exhibits the expected square-root-of-length dependence, corresponding to a polarization-mode dispersion of 0.26 ps/km(1 /2). The results are in excellent agreement with those obtained by a commer cial instrument utilizing Jones matrix eigenanalysis.