Advanced DSP for 400 Gb/s and Beyond Optical Networks
Venue
J. Lightwave Technology, vol. 32 (2014), pp. 2716-2725
Publication Year
2014
Authors
Xiang Zou, Lynn Nelson
BibTeX
Abstract
This paper presents a systematic review of several digital signal processing
(DSP)-enabled technologies recently proposed and demonstrated for high spectral
efficiency (SE) 400 Gb/s–class and beyond optical networks. These include 1) a
newly proposed SE-adaptable optical modulation technology—time-domain hybrid
quadrature amplitude modulation (QAM), 2) two advanced transmitter side digital
spectral shaping technologies—Nyquist signaling (for spectrally-efficient
multiplexing) and digital preequalization (for improving tolerance toward channel
narrowing effects), and 3) a newly proposed training-assisted two-stage carrier
phase recovery algorithm that is designed to address the detrimental cyclic phase
slipping problem with minimal training overhead. Additionally, this paper presents
a novel DSP-based method for mitigation of equalizer-enhanced phase noise
impairments. It is shown that performance degradation caused by the interaction
between the long-memory chromatic dispersion compensating filter/equalizer and
local oscillator laser phase noise can be effectively mitigated by replacing the
commonly used fast single-tap phaserotation-based equalizer (for typical carrier
phase recovery) with a fast multi-tap linear equalizer. Finally, brief reviews of
two high-SE 400 Gb/s-class WDM transmission experiments employing these advanced
DSP algorithms are presented.
