Site: KDD R&D Laboratories
2-1-5 Ohara Kamifukuoka
Date Visited: October 29, 1992
Report Author: V. Chan
Dr. Kazuo Sakai
Dr. Shigeyuki Akiba
Dr. Yuichi Matsushima
Dr. Masatoshi Suzuki
Mr. Shiro Ryu
Mr. Masayoshi Horita
See site report by B. Edelson on Oct. 23, 1992 visit to KDD R&D Labs.
See Edelson site report for overview. This visit (October 29), reported below, focused on fiber optics communications.
KDD R&D Labs has four main research objectives:
The organization chart included in the Edelson site report, Figure KDD.1, presents the structure of KDD R&D Laboratories. The October 29 visit was hosted by the Opto-Electronics and Lightwave Communication Systems Groups. Research efforts at KDD R&D Labs in fiber communications focuses on long-haul, high bit-rate systems (of the order of 5 to 10 Gbits/sec). Both coherent and soliton systems are being pursued.
Coherent systems are being considered for long-haul transmission because the detection mechanism is more immune to spontaneous emission in optical amplifiers. Fiber dispersion is a major concern and IF equalization after optical detection at the receiver is the technique of choice to mitigate this effect. Spectral broadening due to the Kerr effect is also a concern. This effect limits unrepeatered transmission to a few thousand kilometers, depending on the bit rate. Experimental data has confirmed such degradation in long-haul ( > 5,000 km) systems.
Soliton systems are an alternative to coherent systems. A 5 Gbits/sec system using erbium-doped amplifiers has been demonstrated over a 3,000 km fiber optic path. This is typical of results published by AT&T, NTT and NEC.
Activities in the Opto-Electronics Group are categorized into optical semiconductor devices and fluoride-glass fibers. In the optical devices area there are five activities, three of which are detailed below:
KDD R&D Labs is at the forefront of research in long-haul fiber optics communication systems. The techniques used are sophisticated and KDD is, and no doubt will be, a serious player in the long-haul market.