@techreport{TD:100866,
	att_abstract={{We review the recent technology advancements related to the transmission of 400Gb/s, wavelength-division-multiplexed channels for optical networks based on the standard 50GHz grid.  We discuss the enabling modulation, coding, and line system technologies, as well as the existing challenges. Specifically, these technologies include time-domain hybrid 32-64 quadrature amplitude modulation, nearly ideal digital Nyquist pulse shaping, improved channel bandwidth management methods such as end-to-end carrier frequency control and distributed compensation of filtering effects arising from reconfigurable optical add-drop multiplexers, distributed Raman amplification, and powerful forward-error-correction.  We demonstrate 400G transmission on the standard 50GHz grid over meaningful transmission reach for regional and metropolitan applications. However, further studies are needed to fully understand the potential for meeting the requirements of long-haul transmission applications.}},
	att_authors={xz8628, ln4395},
	att_categories={},
	att_copyright={{IEEE}},
	att_copyright_notice={{This version of the work is reprinted here with permission of IEEE for your personal use. Not for redistribution. The definitive version was published in 2012. {{, 2012-10-31}}
}},
	att_donotupload={},
	att_private={false},
	att_projects={},
	att_tags={Optical, Fiber, Spectral efficiency, Modulation, Coherent, 400Gb/s, transmission},
	att_techdoc={true},
	att_techdoc_key={TD:100866},
	att_url={http://web1.research.att.com:81/techdocs_downloads/TD:100866_DS1_2012-04-30T04:08:12.532Z.doc},
	author={Xiang Zhou and Lynn Nelson},
	institution={{OSA/IEEE Journal of Lightwave Technology}},
	month={October},
	title={{400G WDM Transmission on the 50GHz Grid for Future Optical Networks}},
	year=2012,
}