Tokyo, Japan--Fujitsu Limited, Fujitsu Laboratories Ltd., and the University of Tokyo announced the world's first quantum-dot-laser-based 25 Gbps (25G) high-speed data transmission. Quantum-dot lasers are a type of semiconductor laser capable of handling high-speed data transmission while consuming minimal power. Because increasing the number of quantum dots is known to improve a quantum dot laser's operation speed, layers of quantum dots--with a higher density than conventionally used--were stacked, doubling the laser's operation speed and enabling a significant improvement over previous technologies. This laser source could potentially be used in next-generation 40G and 100G optical communications systems.
Part of this research belongs to a project contracted to the Photonics Electronics Technology Research Association (PETRA) by the New Energy and Industrial Technology Development Organization (NEDO), while part of the research was carried out under Japan's Ministry of Education, Culture, Sports, Science and Technology's Special Coordination Funds for Promoting Science and Technology. In addition, joint research and development of quantum dot lasers is being pursued through collaboration between Professor Yasuhiko Arakawa's laboratory at the University of Tokyo, Fujitsu, Fujitsu Laboratories, and QD Laser.
Quantum-dot lasers are semiconductor lasers that use quantum dots--nanometer-sized semiconductor particles as an active material for lasing. Quantum well lasers, which have conventionally been used as optical sources for data communications, have a problem of dramatic increases in power consumption attributable to increased driving current when temperatures rise. The quantum dot laser developed by Fujitsu Laboratories and the University of Tokyo uses 3-dimensional (3D) semiconductor nanostructures to produce quantum effects, giving it excellent characteristics, including stable operation over a range of temperatures and low power consumption. The new technology doubled the number of quantum dots per unit and increased the number of layers.
Fujitsu Laboratories and the University of Tokyo plan to further refine this technology to increase its transmission distance and to confirm reliability for future use in high-speed 100G communications systems. QD Laser is also considering commercializing this technology.
--Posted by Gail Overton; [email protected]; www.laserfocusworld.com