NEC Corporation



Press Release
                        Media Contact: 
                        Daniel Mathieson	
                        NEC Corporation	
                        Tel: +81-3-3798-6511
                        Fax: +81-3-3457-7249
                        d-mathieson@bu.jp.nec.com

*****For immediate use March 22nd, 2001

NEC SETS NEW10.9 TERABIT/SECOND, ULTRA-DENSE WDM TRANSMISSION CAPACITY WORLD RECORD

Breaking the capacity barrier with exclusive S-band amplification technology


TOKYO, March 22, 2001 - NEC Corporation (NEC) (NASDAQ: NIPNY) (FTSE: 6701q.l) (TSE: 6701) a leading solution provider of advanced communication products, software and services for public and private networks, today announced that it has set a new Dense Wavelength Division Multiplexing (DWDM) transmission capacity world record. NEC has successfully transmitted 10.9Tb/s (273 channels, each with 40Gb/s data speed) of information over 117km.

This unprecedented ultra-high capacity was achieved with three breakthrough technologies developed by NEC: (1) the exclusive S-band amplification technology allowing light amplification in the 1490nm wavelength region, (2) optimized system design technology for the ultimate 3-band (the S-band plus the conventional C- and L-bands) transmission, and (3) ultra-dense channel multiplexing technology employing polarization multiplexing/ demultiplexing technique.

This record-setting capacity will allow simultaneous long-distance transmission of more than 1 million high-speed ADSL channels over a single line of fiber, opening the new era of broadband networking applications.

NEC presented the details of this achievement on March 22, at the Optical Fiber Communication Conference (OFC 2001) post-deadline session, held in Anaheim, CA.

Recent advances in the Internet technology have resulted in the massive growth of data traffic demand all over the world. To cope with this traffic demand, WDM technologies have been introduced to cost-effectively upgrade the capacity of already-installed fiber facilities by sending information on different wavelengths (colors) of light. Until now, the long-distance WDM transmission system mainly employed two wavelength bands (wavelength groups): the C-band in the 1550nm wavelength region, and the L-band in the 1580nm wavelength region. By utilizing these two wavelength bands simultaneously, several under-10Tb/s transmission results have already been reported, one of which was 6.4Tb/s capacity demonstrated by NEC. However, to further increase the transmission capacity up to 10Tb/s and beyond, the capability of the two wavelength bands had not been sufficient.

To solve this difficulty, NEC has been undertaking in an intense research and development effort, developing optical amplifiers that operate in the 1490nm wavelength region. The 1490nm wavelength region, called the S-band, is characterized by low signal attenuation next to the C- and the L-bands. With NEC's leading-edge technologies, the world's first S-band amplifier has been developed enabling triple-band transmission on a single line of fiber. This unique S-band amplification technology, together with optimized 3-band transmission system design technology, and polarization multiplexing/ demultiplexing technology, enabled simultaneous transmission of 273 channels each with 40Gb/s data speed, for the total throughput of 10.9Tb/s, nearly double the capacity of the previous 6.4Tb/s record set by NEC.

The main features of the demostration were as follows:

  1. Expansion of the transmission bandwidth from the conventional 64nm to 110nm by developing Thulium-doped fiber amplifiers (TDFAs) that operates in the 1490nm wavelength region. The developed TDFAs employ dual-wavelength pumping using semiconductor laser diodes resulting in high efficiency and high reliability.

  2. Fiber-type optimization and power-level optimization for triple-band transmission to suppress the degradations due to nonlinear effects in optical fibers, resulting in successful repetitive transmission over 117km.

  3. Multiplexing of 40Gb/s channels at 50GHz spacing to achieve the spectral efficiency of 0.8b/s/Hz by utilizing polarization multiplexing/ demultiplexing technique.

NEC is planning to further intensify its research and development effort to make 10Tb/s transmission systems commercially available as soon as possible.

A part of this work was supported by Telecommunication Advancement Organization of Japan.

About NEC Corporation
NEC Corporation (NASDAQ: NIPNY) (FTSE: 6701q.l) (TSE: 6701) is a leading provider of Internet solutions, dedicated to meeting the specialized needs of its customers in the key computer, network and electron device fields through its three market-focused in-house companies: NEC Solutions, NEC Networks and NEC Electron Devices. NEC Corporation, with its in-house companies, employs more than 150,000 people worldwide and saw net sales of 4,991 billion Yen (approx. US$48 billion) in fiscal year 1999-2000. For further information, please visit the NEC home page at: http://www.nec.com

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NEC Corporation