PMD-supported coherent optical OFDM

Although polarization-mode-dispersion (PMD) greatly impairs conventional high-speed single-carrier systems, it is shown that for multi-carrier systems such as coherent optical orthogonal frequency division multiplexed (CO-OFDM) systems, not only does PMD not cause any impairment, but it also provides a benefit of polarization diversity against polarization-dependent-loss (PDL) induced fading and consequently improves the system marginBegin the abstract two lines below author names and addresses. In this paper, we present the model for the optical fiber communication channel in the presence of the polarization effects. It shows that the optical fiber channel model can be treated as a special kind of multiple-input multiple-output (MIMO) model, namely, a two-input two-output (TITO) model which is intrinsically represented by a two-element Jones vector familiar to the optical communications community. The detailed discussions on variations of such coherent optical MlMO-OFDM (CO-MIMO-OFDM) models are presented. Furthermore, we show the first experiment of polarization-diversity detection in CO-OFDM systems. In particular, a CO-OFDM signal at 10.7 Gb/s is successfully recovered after 900 ps differential-group-delay (DGD) and 1000-km transmission through SSMF fiber without optical dispersion compensation. The transmission experiment with higher-order PMD further confirms the resilience of the CO-OFDM signal to PMD in the transmission fiber.