Ultra-High Capacity Optical Transmission Technologies for 100 Tbit/s Optical Transport Networks

Akihide SANO  Takayuki KOBAYASHI  Eiji YOSHIDA  Yutaka MIYAMOTO  

IEICE TRANSACTIONS on Communications   Vol.E94-B   No.2   pp.400-408
Publication Date: 2011/02/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.E94.B.400
Print ISSN: 0916-8516
Type of Manuscript: INVITED PAPER (Special Section on Extremely Advanced Optical Transmission Technologies and Transmission Optical Fiber Technologies towards Exabit Era)
coherent optical communication,  multi-level modulation,  QAM,  Raman amplification,  

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This paper describes ultra-high capacity wavelength-division multiplexed (WDM) transmission technologies for 100-Tbit/s-class optical transport networks (OTNs). First, we review recent advances in ultra-high capacity transmission technologies focusing on spectrally-efficient multi-level modulation techniques and ultra-wideband optical amplification techniques. Next, we describe an ultra-high capacity WDM transmission experiment, in which high speed polarization-division multiplexed (PDM) 16-ary quadrature amplitude modulation (16-QAM), generated by an optical synthesis technique, in combination with coherent detection based on digital signal processing with pilotless algorithms, realize the high spectral efficiency (SE) of 6.4 b/s/Hz. Furthermore, ultra-wideband hybrid optical amplification utilizing distributed Raman amplification (DRA) and C- and extended L-band erbium-doped fiber amplifiers (EDFAs) is shown to realize 10.8-THz total signal bandwidth. By using these techniques, 69.1-Tbit/s transmission is demonstrated over 240-km of pure silica-core fibers (PSCFs). Furthermore, we describe PDM 64-QAM transmission over 160 km of PSCFs with the SE of 9.0 b/s/Hz.