Polarization mode dispersion in dispersion-shifted fibers: an exact analysis

Optical-fiber telecommunication systems operated in the multigigabit-per-second range use circular-core, dispersion- shifted fibers. A slight departure from circularity of the fiber results in polarization mode dispersion (PMD) that has a limiting effect on the bandwidth-distance products.12 Two factors are known to contribute to PMD in a slightly elliptical fiber: (i) form-induced effects, whereby small ovalities affect the waveguide propagation constants of the two fundamental modes, and (ii) material-induced internal stresses in oval fibers, which result in a residual stress anisotropy.