.Maximizing the spectral efficiency of Stokes vector receiver with optical field recovery.

Stokes vector receivers (SVR) bridge the 4-D (i.e. dual-polarization complex signals) coherent detection and the conventional intensity-only 1-D direct detection (DD). By multi-dimensional polarization modulation in Stokes space, SVR maximizes the electrical spectral efficiency (ESE) of DD receivers by recovering at most 3-D signals. However, most 3-D schemes lack the capability of optical field recovery, an essential requirement for digital post-compensation of fiber dispersion that elongates the achievable distance. We propose a 3-D Stokes-space field modulation to enable 3-D signal field recovery, verified by a 3-D 32-Gbaud per dimension probabilistic-constellation-shaped 64-QAM transmission over 260-km fiber at C-band. This sets an ESE record of 16.5 (net ESE of 13.9) bit/s/Hz for DD receivers.