Optical Field Recovery in the Jones Space

 Optical full-field recovery makes it possible to compensate fiber impairments such as chromatic dispersion and polarization mode dispersion (PMD) in the digital signal processing. Coherent detection dominates over the long-haul transmission system due to its high spectral efficiency and tolerance against optical impairments. For cost-sensitive short-reach optical networks, some advanced single-polarization (SP) optical field recovery schemes are recently proposed to avoid chromatic dispersion-induced power fading effect, and improve the spectral efficiency for larger potential capacity. Polarization division multiplexing (PDM) can further double both the spectral efficiency and the system capacity of these SP carrier-assisted direct detection (DD) schemes. However, the so-called polarization fading phenomenon induced by random polarization rotation is a fundamental obstacle to exploit the polarization diversity for carrier-assisted DD systems. In this paper, we propose a receiver of Jones-space field recovery (JSFR) to realize polarization diversity with SP carrier-assisted DD schemes in the Jones space. There different receiver structures of proposed JSFR and the simplification for JSFR are explored theoretically. The proposed JSFR pushes the SP DD schemes towards PDM without no extra optical signal-to-noise ratio (OSNR) penalty. In addition, the JSFR shows good tolerance to PMD since the optical field recovery is conducted before polarization recovery. In the concept-of-proof experiment, we demonstrate 448-Gb/s reception over 80-km single-mode fiber using the proposed JSFR based on 2×2 couplers. Qualitatively, we compare the optical field recovery in the Jones space and Stokes space from the perspective of the modulation dimension.