Japan Semiconductor Innovation 50     (D-13 1990s)

Semiconductor Lasers for Optical Fiber Communications (NTT, KDDI, NEC, Fujitsu, Hitachi)

Tokyo Institute of Technologies (TIT) and NTT succeeded in the worldfs first room-temperature continuous oscillation of InGaAsP/InP lasers in 1976. NEC, Fujitsu, Hitachi and several other Japanese companies followed this achievement and took technical leadership world-wide, by improving the performance of the lasers by various key inventions and development of modified laser structures, such as Distributed-Bragg-Reflector (DBR) lasers, Distributed Feedback-Multiple-Quantum well (DFB-MQW) lasers, and Modulator-Integrated-DFB (MI-DFB) lasers. Crystal growth and fabrication technologies for volume production of these lasers were also established. High capacity optical fiber communication systems were realized by using these lasers, such as Japan end-to-end long-haul trunk optical fiber cable routes in 1985, and the transpacific optical fiber submarine cable system in 1989.
These lasers have played an important role in explosive expansion of high speed, long distance, high capacity communication systems in the world.

Structure of MI-DFB laser

(Fujitsu Sci. Tech. J., 35, p.101 (1999)


To main gallery (Discrete Device 1980s)

Database on Noteworthy Contributions for Science and Technology (Japan)
1) Dynamic Single Mode Lasers and Integrated Lasers ~ Basic Research for Ultra-high Speed and Long Distance Optical Fiber Communications ~

2) Development of optical semiconductor devices for long-distance and high-capacity optical communications