A collaboration between Fujitsu and the University of Tokyo achieved a record 25Gbps data communication link using quantum dot laser, a low-cost technology that can reliably handle high-speed data transmissions while consuming minimal power. With good performance and wide margins for further improvement, this development paves the way to the next generation of high-speed Ethernet data communications, which will see a tenfold increase in transfer speed.
As the video sharing and cloud computing phenomena keep inflating our need for speed, engineers urgently need solutions to keep pace with these growing demands. When it comes to long distances the astronomical speeds and good technical characteristics of fiber optics seem up to the task of meeting our demands for some time to come. But of course, since our personal computers aren't (yet) capable of directly elaborating the light signals from fiber optics, the speed of the end connection becomes just as important.
This explains why this research is newsworthy: quantum dot laser is a semiconductor-based technology that can interface with our home computers, and do so 2.5 times faster than the latest Ethernet standard. This development also comes with excellent timing, since the IEEE has announced it is hoping to create a 100Gbps Ethernet standard by this year's end, which makes quantum dot laser the strongest candidate to date.
One of the main issues with current semiconductor-based data transmission is their very poor stability as the temperature rises, which in turn causes dramatic increases in power consumption. Quantum dot lasers are less sensitive to temperature fluctuations and also offer much lower power consumption, weaker distortion, and faster speeds. The decreased sensitivity to temperature fluctuations also makes temperature controllers superfluous, which helps in lowering costs.
Up to now quantum dot laser technology could only achieve data transfer speeds of up to 10Gbps, but the researchers managed to reach higher speeds by forming high-density indium-arsenide quantum dots on the surface of a gallium-arsenide substrate, which doubles the number of quantum dots per unit area. Additionally, they developed a technology for stacking multiple layers of high-density dots, increasing the number of layers from five to eight.