Second-order polarization mode dispersion: impact on analog and digital transmissions

Second-order polarization mode dispersion (PMD) is a major limitation to the transmission capabilities of analog systems and of high bit rate digital systems. Basically, the effect of second-order PMD is the same as that of chromatic dispersion. However, like all polarization effects in standard single-mode fibers, the effects of second-order PMD are stochastic, due to the random polarization mode coupling that occurs in such fibers. Hence, the effects of second-order PMD fluctuate with time. The purpose of this article is to present a description of the phenomenon and of its effects on analog and digital signals, to propose definitions, to discuss some orders of magnitudes and to present some numerical simulations and experimental results. Some general understanding of the phenomena of first-order PMD are assumed.