Space-time codes for optical fiber communication with polarization multiplexing

Polarization effects may induce severe performances degradation in polarization multiplexed optical fiber transmissions. Those systems can be seen as 2x2 multi-antennas systems as the emitted polarizations can be considered as 2 input signals and the received polarizations as 2 output signals. Therefore, Space-Time code can be used to take benefit of this configuration and enhance the transmission performances but they have to be combined with optical OFDM to suppress the fiber dispersion and allow their decoding. In wireless 2x2 multi-antennas systems, the Golden and the Silver code are respectively the two best Space-Time codes so, we propose to use those two codes on polarization multiplexed systems. The performances of the Space-Time codes on the optical fiber channel are different than on the wireless channel. Simulations show than the Silver code outperforms the Golden code. Nevertheless, we also show that Space-Time coding can dramatically mitigate the polarization dependent loss (PDL) impairments.