Performance analysis of DPSK direct detection optical systems in the presence of interferometric intensity noise

The performance of DPSK direct detection optical systems using a dual detector receiver is analyzed by means of a Gauss quadrature rules method. The filtering effects on the intensity noise, resulting from the interferometric conversion of laser phase noise, and the influence of laser relaxation oscillations are also investigated. Linewidth requirements are estimated and compared with that of DPSK heterodyne systems. It is shown that linewidth requirements can be relaxed by a factor of about 0.56, when baseband filtering effects are taken into account.<
>