Disjoint detection in polarization multiplexed communication systems affected by polarization dependent loss

We study the performance of a simple optical receiver for use with polarization multiplexed transmission in the presence of polarization dependent loss (PDL). The receiver is based upon filtering of each of the channels with a polarizer that is orthogonal to the other channel, such that interference due to loss of orthogonality is avoided at the expense of a reduction in the detected signal to noise ratio. In spite of its simplicity, this receiver is shown to perform almost as well as the optimal maximum likelihood receiver, and much better than receivers that are based on conventional polarization splitting.