[OPTICAL REVIEW Vol. 7, No. 1 (2000) 1-8]

Recent Progress of Wavelength Division Multiplexing Technology In Tera-bit/s Transoceanic Undersea Cable Systems

Masatoshi SUZUKI and Kazuo SAKAI

KDD R&D Laboratories Inc., 2-1-15, Ohara, Kamifukuoka-shi, Saitama, 356-8502 Japan

(Received November 25, 1999; accepted December 2, 1999)

Transmission capacity for optical undersea cable systems is growing remarkably and a more than 500-fold increase has been achieved for commercial systems over the past 10 years. The first optical fiber cable in the Pacific Ocean went into service in 1989 and has a capacity of 280 Mbit/s per fiber pair. The emergence of an Erbium-doped fiber amplifier paved the way for a drastic capacity increase for these cables, and large capacity optical amplifier undersea cable systems with 5 Gbit/s per fiber pair were constructed worldwide in 1995-1996. Recent 10 Gbit/s-based wavelength division multiplexing (WDM) technologies together with new fibers and new amplifiers have allowed a further increase in capacity up to 160 Gbit/s, and these WDM systems will begin commercial service in both the Pacific Ocean and the Atlantic Ocean in 2000. Research interest is now being directed towards the development of undersea cable systems with a transmission capacity of 1 Tera-bit/s or more. This paper reviews the key technologies for next generation 160 Gbit/s optical undersea cable systems and recent progress towards Tera-bit/s systems. Dispersion managed soliton transmission for future higher bit rate WDM is also discussed.

Key words : optical fiber transmission systems, undersea cable, wavelength division multiplexing, optical amplifier, dispersion management, fiber nonlinearity, dispersion managed soliton, Tera-bit/s transmission