Performance comparison among three different Stokes vector direct detection rece

Stokes vectors direct detection (SV-DD) is an effective solution for short-reach optical communications. In this Letter, we investigate two-dimensional-modulation direct-detection systems based on three Stokes vector receivers (SVRs). The influences of three key factors including the states-of-polarization (SOP), the splitting ratio of the coupler, and the excess loss (EL) are studied in detail. It is shown that the splitting ratio for achieving optimum performance will be changed with SOP and E