Advanced DSP for 400Gb/s and beyond Optical Networks
Venue
JOURNAL OF LIGHTWAVE TECHNOLOGY, vol. Vol. 32 (2014), pp. 2716-2725
Publication Year
2014
Authors
Xiang Zhou, 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) 400Gb/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 pre-equalization (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 (CD) compensating filter/equalizer and
local oscillator (LO) laser phase noise can be effectively mitigated by replacing
the commonly used fast single-tap phase-rotation-based equalizer (for typical
carrier phase recovery) with a fast multi-tap linear equalizer. Finally, brief
reviews of two high-SE 400Gb/s-class WDM transmission experiments employing these
advanced DSP algorithms are presented.
