Penalties induced by higher-order PMD at 10 Gbit/s in nondispersion-shifted fibers

In a recently published work see, Electron. Lett., vol.31, p.1597, 1995; we have demonstrated theoretically that in nondispersion-shifted fibers, second-order polarization-mode dispersion (PMD) can severely compound the PMD penalty as a result of first-order PMD [i.e., the value of the differential group delay (DGD) at the signal central frequency]. To verify these theoretical results, a l0-Gbit/s nonreturn to zero (NRZ) transmission was set up over a 70 km nondispersion-shifted fiber with a chromatic dispersion near 1550 nm. The l0-Gbit/s transmitter consisted of a modulated DFB laser.