DSP Technologies in Stokes Vector Receivers for Short-reach Optical Transmission Systems

摘要

Stokes vector receivers have attracted attention for their ability to enhance spectral efficiency due to the increase in the number of dimensions compared to conventional intensity-modulation and direct-detection (IM-DD) systems. One of the technical advantages of the Stokes receiver is that the original state-of-polarization (SOP) of a transmitted signal can be retrieved with digital signal processing (DSP) even if it is fluctuated during fiber transmission. In this paper, we review DSP technologies for SOP recovery, focusing on the modified constant modulus algorithm (CMA), and the radius directed equalization (RDE) algorithm in the Stokes space. Using computer simulations, we show that these algorithms can track random SOP fluctuations without any penalties.