Periodic compensation of polarization mode dispersion

Polarization mode dispersion is the effect of signal broadening in a fiber with birefringent disorder. The disorder, frozen into the fiber, is characterized by the so-called vector of birefringence (VB). In a linear medium a pulse broadens as the two principal states of polarization split. It is well-known that, under the action of short-correlated disorder, naturally present in fibers, the dispersion vector (DV), characterizing the split, performs a Brownian random walk. We discuss a strategy of passive (i.e., pulse-independent) control of the DV broadening. The suggestion is to pin (compensate) periodically or quasi-periodically the integral of VB to zero. As a result of the influence of pinning, the probability distribution function of the DV becomes statistically steady in the linear case. Moreover, pinning improves confinement of the pulse in the weakly nonlinear case. The theoretical findings are confirmed by numerical analysis.